Add settings page with CSV export, SQL dump export/import

New /settings page (linked from the header's burger menu) offers:
- CSV export of the user's links, for spreadsheet apps.
- SQL dump export as INSERT INTO links (...) statements, scoped to
  the current user only — never a raw full-database dump, since that
  would leak other accounts' password hashes and data. Embeddings are
  excluded (regenerated via "KI neu beschreiben lassen" if needed).
- SQL import that re-adds a previously exported dump to the current
  account (additive, doesn't touch existing links).

Import safety (app/backup.py): uploaded SQL is never executed against
the real database. Each non-comment line is required to start with
"insert into links" and is run one statement at a time against an
isolated in-memory SQLite database with only a whitelisted `links`
schema (no id/user_id columns) — sqlite3.execute() also rejects
multiple statements per call. Only after that succeeds are rows
copied into the real DB via the ORM, with user_id forced to the
logged-in user. Verified this rejects DROP TABLE, ATTACH DATABASE,
stacked statements, cross-table subqueries, and user_id injection.
Upload is capped at 2 MB.

Also adds download/upload icons and a proper file-input styling
pattern (visually-hidden input + <label> trigger + filename readout),
since the browser's ::file-selector-button pseudo-element didn't
render reliably in testing.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/backup.py

@@ -0,0 +1,105 @@
+"""CSV-/SQL-Export und SQL-Import der eigenen Links (Backup & Restore)."""
+
+import csv
+import io
+import sqlite3
+
+from .models import Link
+
+SQL_COLUMNS = [
+    "url", "title", "summary", "category", "manufacturer",
+    "tags", "status", "needs_review", "created_at",
+]
+
+
+def to_csv(links: list[Link]) -> str:
+    buf = io.StringIO()
+    writer = csv.writer(buf)
+    writer.writerow(
+        ["url", "title", "summary", "category", "manufacturer", "tags", "status", "created_at"]
+    )
+    for link in links:
+        writer.writerow(
+            [
+                link.url,
+                link.title,
+                link.summary,
+                link.category,
+                link.manufacturer,
+                ", ".join(link.tag_list),
+                link.status,
+                link.created_at.isoformat(),
+            ]
+        )
+    return buf.getvalue()
+
+
+def _sql_quote(value: str) -> str:
+    return "'" + value.replace("'", "''") + "'"
+
+
+def to_sql_dump(links: list[Link]) -> str:
+    lines = [
+        "-- LinkVault-Export – Links des angemeldeten Kontos.",
+        "-- Kann über 'Einstellungen -> SQL-Import' wieder eingespielt werden.",
+        f"-- Zeilen: {len(links)}",
+        "",
+    ]
+    for link in links:
+        values = ", ".join(
+            [
+                _sql_quote(link.url),
+                _sql_quote(link.title),
+                _sql_quote(link.summary),
+                _sql_quote(link.category),
+                _sql_quote(link.manufacturer),
+                _sql_quote(link.tags),
+                _sql_quote(link.status),
+                "1" if link.needs_review else "0",
+                _sql_quote(link.created_at.isoformat()),
+            ]
+        )
+        lines.append(f"INSERT INTO links ({', '.join(SQL_COLUMNS)}) VALUES ({values});")
+    return "\n".join(lines) + "\n"
+
+
+def parse_sql_dump(sql_text: str, max_rows: int = 5000) -> list[dict]:
+    """Liest die von to_sql_dump() erzeugten INSERT-Zeilen sicher ein.
+
+    Läuft bewusst gegen eine isolierte In-Memory-SQLite-Datenbank statt gegen
+    die echte App-Datenbank: nur Zeilen, die (nach Trimmen) mit
+    'insert into links' beginnen, werden ausgeführt, und sqlite3.execute()
+    lässt ohnehin nur je eine einzelne Anweisung zu. Dadurch können weder
+    andere Tabellen berührt noch mehrere Anweisungen aneinandergehängt werden.
+    Das Ergebnis wird anschließend vom Aufrufer kontrolliert per ORM in die
+    echte Datenbank übernommen (mit fest gesetzter user_id).
+    """
+    conn = sqlite3.connect(":memory:")
+    try:
+        conn.execute(
+            "CREATE TABLE links ("
+            "url TEXT, title TEXT, summary TEXT, category TEXT, manufacturer TEXT, "
+            "tags TEXT, status TEXT, needs_review INTEGER, created_at TEXT)"
+        )
+        statements = 0
+        for raw_line in sql_text.splitlines():
+            line = raw_line.strip()
+            if not line or line.startswith("--"):
+                continue
+            if not line.lower().startswith("insert into links"):
+                continue
+            if statements >= max_rows:
+                raise ValueError(f"Zu viele Zeilen (Limit: {max_rows}).")
+            try:
+                conn.execute(line)
+            except sqlite3.Error as e:
+                raise ValueError(f"Ungültige Zeile: {e}") from e
+            statements += 1
+
+        if statements == 0:
+            raise ValueError("Keine gültigen INSERT-Zeilen für 'links' gefunden.")
+
+        cur = conn.execute(f"SELECT {', '.join(SQL_COLUMNS)} FROM links")
+        return [dict(zip(SQL_COLUMNS, row)) for row in cur.fetchall()]
+    finally:
+        conn.close()

app/main.py

@@ -1,18 +1,18 @@
 import json
 from datetime import datetime, timezone
 from pathlib import Path
-from urllib.parse import urlparse
+from urllib.parse import quote, urlparse
 
-from fastapi import Depends, FastAPI, Form, Request
+from fastapi import Depends, FastAPI, File, Form, Request, UploadFile
 from fastapi.responses import HTMLResponse, RedirectResponse, Response
 from fastapi.templating import Jinja2Templates
 from sqlalchemy import func, select, text
 from sqlalchemy.orm import Session
 from starlette.middleware.sessions import SessionMiddleware
 
-from . import ai, config, scraper, search
+from . import ai, backup, config, scraper, search
 from .database import Base, engine, get_db
-from .models import Link, User
+from .models import Link, User, utcnow
 from .security import hash_password, verify_password
 
 Base.metadata.create_all(bind=engine)
@@ -529,3 +529,126 @@ def reanalyze_link(
     return templates.TemplateResponse(
         "_link_card_edit.html", _edit_context(request, db, user, link)
     )
+
+
+# ---------------------------------------------------------------------------
+# Einstellungen: Export / Import
+# ---------------------------------------------------------------------------
+MAX_IMPORT_BYTES = 2 * 1024 * 1024
+
+
+@app.get("/settings", response_class=HTMLResponse)
+def settings_page(request: Request, db: Session = Depends(get_db)):
+    user = current_user(request, db)
+    if not user:
+        return RedirectResponse("/login", status_code=303)
+    link_count = db.scalar(
+        select(func.count()).select_from(Link).where(Link.user_id == user.id)
+    )
+    return templates.TemplateResponse(
+        "settings.html",
+        {
+            "request": request,
+            "user": user,
+            "link_count": link_count or 0,
+            "imported": request.query_params.get("imported"),
+            "import_error": request.query_params.get("import_error"),
+        },
+    )
+
+
+@app.get("/settings/export.csv")
+def export_csv(request: Request, db: Session = Depends(get_db)):
+    user = current_user(request, db)
+    if not user:
+        return RedirectResponse("/login", status_code=303)
+    links = list(
+        db.scalars(
+            select(Link).where(Link.user_id == user.id).order_by(Link.created_at)
+        ).all()
+    )
+    return Response(
+        backup.to_csv(links),
+        media_type="text/csv; charset=utf-8",
+        headers={"Content-Disposition": "attachment; filename=linkvault-links.csv"},
+    )
+
+
+@app.get("/settings/export.sql")
+def export_sql(request: Request, db: Session = Depends(get_db)):
+    user = current_user(request, db)
+    if not user:
+        return RedirectResponse("/login", status_code=303)
+    links = list(
+        db.scalars(
+            select(Link).where(Link.user_id == user.id).order_by(Link.created_at)
+        ).all()
+    )
+    return Response(
+        backup.to_sql_dump(links),
+        media_type="application/sql; charset=utf-8",
+        headers={"Content-Disposition": "attachment; filename=linkvault-links.sql"},
+    )
+
+
+@app.post("/settings/import-sql")
+async def import_sql(
+    request: Request,
+    file: UploadFile = File(...),
+    db: Session = Depends(get_db),
+):
+    user = current_user(request, db)
+    if not user:
+        return RedirectResponse("/login", status_code=303)
+
+    raw = await file.read(MAX_IMPORT_BYTES + 1)
+    if len(raw) > MAX_IMPORT_BYTES:
+        return RedirectResponse(
+            f"/settings?import_error={quote('Datei ist größer als 2 MB.')}",
+            status_code=303,
+        )
+    try:
+        sql_text = raw.decode("utf-8")
+    except UnicodeDecodeError:
+        return RedirectResponse(
+            f"/settings?import_error={quote('Datei ist keine gültige UTF-8-Textdatei.')}",
+            status_code=303,
+        )
+
+    try:
+        rows = backup.parse_sql_dump(sql_text)
+    except ValueError as e:
+        return RedirectResponse(f"/settings?import_error={quote(str(e))}", status_code=303)
+
+    imported = 0
+    for row in rows:
+        url = (row.get("url") or "").strip()[:2000]
+        if not url:
+            continue
+        created_at = utcnow()
+        if row.get("created_at"):
+            try:
+                created_at = datetime.fromisoformat(row["created_at"])
+            except ValueError:
+                pass
+        try:
+            tags = json.dumps(json.loads(row.get("tags") or "[]"), ensure_ascii=False)
+        except (ValueError, TypeError):
+            tags = "[]"
+        db.add(
+            Link(
+                user_id=user.id,
+                url=url,
+                title=(row.get("title") or "").strip()[:300],
+                summary=(row.get("summary") or "").strip()[:1000],
+                category=(row.get("category") or "").strip()[:120],
+                manufacturer=(row.get("manufacturer") or "").strip()[:120],
+                tags=tags,
+                status=(row.get("status") or "ok").strip()[:20] or "ok",
+                needs_review=bool(row.get("needs_review")),
+                created_at=created_at,
+            )
+        )
+        imported += 1
+    db.commit()
+    return RedirectResponse(f"/settings?imported={imported}", status_code=303)

app/templates/_icons.html

@@ -74,6 +74,14 @@
 {{ base('<line x1="21" x2="14" y1="4" y2="4"/><line x1="10" x2="3" y1="4" y2="4"/><line x1="21" x2="12" y1="12" y2="12"/><line x1="8" x2="3" y1="12" y2="12"/><line x1="21" x2="16" y1="20" y2="20"/><line x1="12" x2="3" y1="20" y2="20"/><line x1="14" x2="14" y1="2" y2="6"/><line x1="8" x2="8" y1="10" y2="14"/><line x1="16" x2="16" y1="18" y2="22"/>', size) }}
 {%- endmacro %}
 
+{% macro download(size=16) -%}
+{{ base('<path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/><polyline points="7 10 12 15 17 10"/><line x1="12" x2="12" y1="15" y2="3"/>', size) }}
+{%- endmacro %}
+
+{% macro upload(size=16) -%}
+{{ base('<path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/><polyline points="17 8 12 3 7 8"/><line x1="12" x2="12" y1="3" y2="15"/>', size) }}
+{%- endmacro %}
+
 {% macro tag(size=16) -%}
 {{ base('<path d="M12.586 2.586A2 2 0 0 0 11.172 2H4a2 2 0 0 0-2 2v7.172a2 2 0 0 0 .586 1.414l8.704 8.704a2.426 2.426 0 0 0 3.42 0l6.58-6.58a2.426 2.426 0 0 0 0-3.42z"/><circle cx="7.5" cy="7.5" r="1.5"/>', size) }}
 {%- endmacro %}

app/templates/base.html

@@ -59,6 +59,15 @@
       background: var(--panel2); border: 1px solid var(--border); color: var(--text);
       border-radius: 8px; padding: 10px 12px; font-size: .95rem; width: 100%;
     }
+    .file-input {
+      position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
+      overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
+    }
+    .file-label {
+      display: inline-flex; align-items: center; gap: 6px; cursor: pointer;
+      white-space: nowrap;
+    }
+    .file-label:focus-within { outline: 2px solid var(--accent); outline-offset: 2px; }
     input:focus, select:focus { outline: none; border-color: var(--accent); }
     select {
       background: var(--panel2); border: 1px solid var(--border); color: var(--text);

app/templates/index.html

@@ -27,9 +27,9 @@
         <button type="button" class="dropdown-item" disabled>
           {{ icons.tag(size=15) }} Tags verwalten <span class="soon">bald</span>
         </button>
-        <button type="button" class="dropdown-item" disabled>
-          {{ icons.sliders(size=15) }} Einstellungen <span class="soon">bald</span>
-        </button>
+        <a href="/settings" class="dropdown-item" style="text-decoration:none;">
+          {{ icons.sliders(size=15) }} Einstellungen
+        </a>
         <div class="dropdown-sep"></div>
         <form method="post" action="/logout" style="margin:0;">
           <button type="submit" class="dropdown-item">{{ icons.log_out(size=15) }} Abmelden</button>

app/templates/settings.html

@@ -0,0 +1,84 @@
+{% extends "base.html" %}
+{% import "_icons.html" as icons %}
+{% block title %}Einstellungen · LinkVault{% endblock %}
+{% block body %}
+<header class="topbar">
+  <a href="/" class="brand">Link<span>Vault</span></a>
+  <div class="user-info">
+    <button id="theme-toggle" type="button" class="ghost icon-btn" title="Farbschema wechseln">
+      <span class="theme-icon-dark">{{ icons.moon() }}</span>
+      <span class="theme-icon-light">{{ icons.sun() }}</span>
+    </button>
+    <a href="/" class="ghost icon-btn" title="Zurück zu den Links">{{ icons.grid() }}</a>
+  </div>
+</header>
+
+<div class="layout" style="max-width:720px; margin-left:auto; margin-right:auto;">
+  <main class="main">
+    <h1 style="margin-top:0;">Einstellungen</h1>
+    <p class="muted" style="margin-top:-8px;">
+      Angemeldet als {{ user.email }} &middot; {{ link_count }} Link{{ '' if link_count == 1 else 'e' }}
+    </p>
+
+    {% if imported is not none %}
+    <div class="panel" style="border-color:#16a34a;">
+      {{ icons.sparkles(size=15) }} {{ imported }} Link{{ '' if imported == '1' else 'e' }} erfolgreich importiert.
+    </div>
+    {% endif %}
+    {% if import_error %}
+    <div class="error">{{ import_error }}</div>
+    {% endif %}
+
+    <div class="panel">
+      <h2 style="margin-top:0; font-size:1.05rem;">CSV-Export</h2>
+      <p class="muted">
+        Alle deine Links als CSV-Tabelle (Titel, Zusammenfassung, Kategorie,
+        Hersteller, Tags, Datum) – zum Öffnen in Excel/Numbers/Sheets.
+      </p>
+      <a href="/settings/export.csv"><button type="button">{{ icons.download(size=14) }} CSV herunterladen</button></a>
+    </div>
+
+    <div class="panel">
+      <h2 style="margin-top:0; font-size:1.05rem;">Datenbank-Export (SQL-Dump)</h2>
+      <p class="muted">
+        Alle deine Links als SQL-<code>INSERT</code>-Anweisungen – als Backup
+        oder zum späteren Wiedereinspielen über den SQL-Import unten.
+        Enthält keine Embeddings (semantische Suche wird beim nächsten
+        „KI neu beschreiben lassen" pro Link neu erzeugt).
+      </p>
+      <a href="/settings/export.sql"><button type="button">{{ icons.download(size=14) }} SQL-Dump herunterladen</button></a>
+    </div>
+
+    <div class="panel">
+      <h2 style="margin-top:0; font-size:1.05rem;">SQL-Import</h2>
+      <p class="muted">
+        Eine mit obigem SQL-Export erzeugte Datei wieder einspielen. Die
+        Links werden deinem Konto <strong>hinzugefügt</strong> (keine
+        bestehenden Links werden überschrieben oder gelöscht). Nur Dateien,
+        die dem Export-Format dieser App entsprechen, werden akzeptiert
+        (max. 2&nbsp;MB).
+      </p>
+      <form method="post" action="/settings/import-sql" enctype="multipart/form-data"
+            style="display:flex; gap:12px; flex-wrap:wrap; align-items:center;">
+        <input type="file" name="file" id="sql-import-file" accept=".sql,text/plain" required class="file-input">
+        <label for="sql-import-file" class="ghost file-label" style="padding:9px 16px; border-radius:8px; border:1px solid var(--border);">
+          {{ icons.upload(size=14) }} Datei wählen
+        </label>
+        <span id="sql-import-filename" class="muted" style="font-size:.85rem;">Keine Datei ausgewählt</span>
+        <button type="submit" style="margin-left:auto;">Importieren</button>
+      </form>
+    </div>
+  </main>
+</div>
+<script>
+  (function () {
+    var input = document.getElementById('sql-import-file');
+    var label = document.getElementById('sql-import-filename');
+    if (input && label) {
+      input.addEventListener('change', function () {
+        label.textContent = input.files && input.files[0] ? input.files[0].name : 'Keine Datei ausgewählt';
+      });
+    }
+  })();
+</script>
+{% endblock %}