feat: role-scoped viewer tokens — restrict shared links to student or staff items

Add a Role scope dropdown to the Share modal (All roles / Ansatte / Elever).
Scope is stored as {"role": "student"|"staff"} in viewer_tokens.json and
enforced server-side in GET /api/db/flagged via session["viewer_scope"].
Client-side, #filterRole is pre-set and hidden for scoped viewers so the
constraint cannot be bypassed. Existing tokens and PIN sessions remain
unrestricted. Role badge shown on each scoped token row in the Active links list.

Files: app_config.py, routes/viewer.py, routes/database.py, gdpr_scanner.py,
templates/index.html, static/js/viewer.js, static/js/auth.js,
lang/en.json, lang/da.json, lang/de.json,
CLAUDE.md, CHANGELOG.md, README.md, MANUAL-EN.md, MANUAL-DA.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -44,9 +44,12 @@ Read-only access for DPOs and reviewers. Key invariants:
 
 - **`/view` auth chain** — token (`?token=`) → session cookie (`session["viewer_ok"]`) → PIN form (if PIN configured) → 403. Never skip this order.
 - **`window.VIEWER_MODE`** — injected by Jinja2 in `index.html`. `auth.js` reads it at startup; adds `viewer-mode` class to `<body>`. All hide rules are CSS (`body.viewer-mode …`), not scattered JS checks — except `delBtn` in the card builder which is also guarded in JS. Hidden in viewer mode: `.sidebar` (entire left panel), `#logWrap`, `#progressBar`, scan/stop/profile/bulk-delete buttons, share button.
-- **`viewer_tokens.json` format** — stored as `{"tokens": [...], "__pin__": {"hash": "…", "salt": "…"}}`. The old bare-list format is migrated transparently on first write. Do not write the file as a bare list.
+- **`window.VIEWER_SCOPE`** — injected alongside `VIEWER_MODE`. Contains the scope dict from the token (e.g. `{"role": "student"}`). Empty object `{}` means unrestricted. `auth.js` reads it at startup; if `VIEWER_SCOPE.role` is set, it pre-sets `#filterRole` to that value and hides the dropdown so the viewer cannot change it.
+- **Token scope** — stored as `"scope": {"role": "student"|"staff"}` or `"scope": {}` in each token dict inside `viewer_tokens.json`. Enforced in two places: server-side (`GET /api/db/flagged` skips items whose `role` column does not match `session["viewer_scope"].role`) and client-side (the `#filterRole` dropdown is locked). Server-side is the authoritative guard.
+- **`session["viewer_scope"]`** — set when a token is validated at `/view`. Persists for the browser session alongside `session["viewer_ok"]`. Reads from `session.get("viewer_scope", {})` in `/api/db/flagged` — defaults to `{}` (unrestricted) for PIN-authenticated sessions and legacy tokens without a scope key.
+- **`viewer_tokens.json` format** — stored as `{"tokens": [...], "__pin__": {"hash": "…", "salt": "…"}}`. Token dicts now include `"scope": {}`. The old bare-list format and tokens without a `scope` key are handled transparently (`t.get("scope", {})`). Do not write the file as a bare list.
 - **`app.secret_key`** — derived from `machine_id` bytes so Flask sessions survive restarts. Set once at startup in `gdpr_scanner.py`; do not override it.
-- **`GET /api/db/flagged`** — returns `get_session_items()` (last completed scan session, joined with dispositions). Used exclusively by `_loadViewerResults()` in `results.js`. Do not confuse with `get_flagged_items()` (single scan_id, no disposition join).
+- **`GET /api/db/flagged`** — returns `get_session_items()` (last completed scan session, joined with dispositions), filtered by `session["viewer_scope"].role` when set. Used exclusively by `_loadViewerResults()` in `results.js`. Do not confuse with `get_flagged_items()` (single scan_id, no disposition join).
 - **Rate-limit state** (`_pin_attempts` dict in `routes/viewer.py`) — in-memory only, resets on server restart. Intentional — a restart clears lockouts without a persistent store.
 - **Token onclick attributes** — Copy/Revoke buttons in `_renderTokenList()` pass the token as a single-quoted JS string literal (`'\'' + tok.token + '\''`), never via `JSON.stringify`. `JSON.stringify` produces double-quoted strings that break the surrounding `onclick="…"` HTML attribute.
 - **Settings Security pane** — Admin PIN and Viewer PIN groups live in `stPaneSecurity`, not `stPaneGeneral`. `switchSettingsTab('security')` in `sources.js` triggers both `stLoadPinStatus()` and `stLoadViewerPinStatus()`. The Share modal Configure button opens `openSettings('security')`.