fix(security,perf): harden restore, CSRF, token_version + perf pass

Security
- Sign pending_restore.json (SHA256 stored in AppSetting, verified on
  startup apply) + refuse path outside data_dir, tighten to 0600.
- Require same-origin Origin/Referer on POST /api/backup/apply-restart —
  Bearer-in-localStorage is CSRF-reachable from any XSS'd admin tab.
- Bump token_version on role/username change and admin password reset so
  demoted admins lose admin in already-issued JWTs.  Guard last-admin
  TOCTOU via COUNT + post-commit re-check that rolls back a race.
- SSRF guard (validate_outbound_url) in ImmichClient.__init__ and the
  external_domain setter — admin-mutable URLs were bypassing the check
  that webhook/slack/discord paths already used.  Dev restart script now
  sets NOTIFY_BRIDGE_ALLOW_PRIVATE_URLS=1 so homelab Immich still works.
- Redact + cap Immich error bodies to ~120 chars before they flow into
  ActionExecution.error / EventLog.details (both UI-visible).
- Deny-list sensitive keys (api_key / token / secret / password /
  authorization / cookie / ...) in template-context merges so a rogue
  template can't exfiltrate provider creds via {{ api_key }}.
- Cap user-controlled Immich search params (query ≤256, person_ids ≤50,
  size ≤100) so a Telegram listener can't DoS upstream.
- Stream upload reads with running byte counter + content-length precheck
  instead of buffering the full body and then rejecting.
- Log Telegram parse_mode fallbacks instead of swallowing silently;
  template escape bugs now surface in server logs.
- Rollback partial imports on pending-restore failure (error recorded on
  a fresh session).

Performance
- Fix N+1 in _refresh_telegram_chat_titles: single IN query instead of
  session.get per chat.
- Parallelize album + shared-link fetches in test_dispatch (asyncio.gather)
  and per-receiver Telegram test sends in notifier (semaphore 5).
- Early-exit collect_scheduled_assets(limit=0) so the periodic-summary
  test path skips full per-album filter/sample (was O(album_assets)).
- Emit explicit CREATE INDEX IF NOT EXISTS for event_log user_id /
  action_id / provider_id so the first boot after upgrade isn't left
  unindexed for the dashboard query.
- Add AbortController timeout (120s) to fetchAuth so uploads/downloads
  don't hang indefinitely.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/server/src/notify_bridge_server/api/users.py

@@ -4,6 +4,7 @@ import logging
 
 from fastapi import APIRouter, Depends, HTTPException, status
 from pydantic import BaseModel
+from sqlalchemy import func
 from sqlmodel import select
 from sqlmodel.ext.asyncio.session import AsyncSession
 
@@ -81,6 +82,12 @@ async def update_user(
     if not user:
         raise HTTPException(status_code=404, detail="User not found")
 
+    # Track whether the identity that JWTs encode has changed. Any such change
+    # must bump ``token_version`` so already-issued tokens are rejected — a
+    # user demoted admin→user must not keep admin in their cached JWT until
+    # expiry, and a rename should invalidate prior sessions too.
+    identity_changed = False
+
     if body.username is not None and body.username != user.username:
         new_username = body.username.strip()
         if not new_username:
@@ -89,21 +96,51 @@ async def update_user(
         if dup.first():
             raise HTTPException(status_code=409, detail="Username already exists")
         user.username = new_username
+        identity_changed = True
 
     if body.role is not None and body.role != user.role:
         if body.role not in ("admin", "user"):
             raise HTTPException(status_code=400, detail="Invalid role")
-        # Prevent demoting the last admin
+        # Prevent demoting the last admin. Done via a COUNT to avoid loading
+        # every admin row; more importantly, re-checked *after* the role
+        # change is staged (TOCTOU guard — two concurrent demotes can each
+        # see admin_count=2 and both proceed, dropping to 0).
         if user.role == "admin" and body.role != "admin":
-            admins = (await session.exec(
-                select(User).where(User.role == "admin")
-            )).all()
-            if len(admins) <= 1:
+            admin_count = (await session.exec(
+                select(func.count(User.id)).where(User.role == "admin")
+            )).one()
+            if isinstance(admin_count, tuple):
+                admin_count = admin_count[0]
+            if (admin_count or 0) <= 1:
                 raise HTTPException(status_code=400, detail="Cannot demote the last admin")
         user.role = body.role
+        identity_changed = True
+
+    if identity_changed:
+        user.token_version = (user.token_version or 1) + 1
 
     session.add(user)
-    await session.commit()
+    try:
+        await session.commit()
+    except Exception:
+        await session.rollback()
+        raise
+
+    # Final defense against admin-count race: if we just demoted the last admin
+    # due to a concurrent demote landing between our check and commit, undo.
+    if body.role is not None and body.role != "admin":
+        admin_count_after = (await session.exec(
+            select(func.count(User.id)).where(User.role == "admin")
+        )).one()
+        if isinstance(admin_count_after, tuple):
+            admin_count_after = admin_count_after[0]
+        if (admin_count_after or 0) < 1:
+            # Roll the user back to admin and re-commit.
+            user.role = "admin"
+            session.add(user)
+            await session.commit()
+            raise HTTPException(status_code=409, detail="Refused: would remove the last admin")
+
     await session.refresh(user)
     return {"id": user.id, "username": user.username, "role": user.role}
 
@@ -126,6 +163,9 @@ async def reset_user_password(
     if len(body.new_password) < 8:
         raise HTTPException(status_code=400, detail="Password must be at least 8 characters")
     user.hashed_password = bcrypt.hashpw(body.new_password.encode(), bcrypt.gensalt()).decode()
+    # Invalidate all prior JWTs issued for this user — matches the self-serve
+    # password-change path in auth/routes.py.
+    user.token_version = (user.token_version or 1) + 1
     session.add(user)
     await session.commit()
     return {"success": True}