Harden the API and the data layer after a security and performance audit

Security
- Every route now requires a login and refuses ids outside the caller's
  workspace with 404: plan, leave-wishes, day-overrides and vacation-days
  were fully anonymous; every other router trusted client-supplied
  workspace/child/parent ids. Scraper sessions are bound to their owner.
- Invitations can no longer be created for a foreign workspace, and a
  redeemer who is already a member (or a full workspace) is refused.
- Production refuses the default JWT secret; API docs are hidden in
  production; a failed migration aborts startup instead of serving.
- Login and register no longer reveal whether an email exists; inactive
  accounts are rejected; /auth/refresh is rate limited.
- The FK scraper writes debug artefacts only when explicitly enabled,
  logs no scraped values or page text, clears the BankID QR as soon as it
  is scanned and purges finished sessions after five minutes.
- Real FK page captures are removed from the tree (history rewrite
  follows); the parser tests use a synthetic fixture.

Performance and correctness
- Plan apply/sync run inside one locked transaction with batched writes
  instead of one commit per row, so a failure mid-batch leaves nothing
  half-applied and concurrent syncs no longer corrupt each other.
- SQLite runs in WAL mode with a busy timeout; 14 indexes cover the
  filters that were full scans; argon2 hashing runs off the event loop;
  responses are gzipped.
- Frontend: a 401 now refreshes the token once and retries, so sessions
  no longer die silently after 15 minutes; every data hook discards
  stale responses; logout clears state even when the server call fails.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CsXCCcDfmV4Sps4ZQSvNEY

backend/app/services/leave_wish_service.py

@@ -89,9 +89,15 @@ class LeaveWishService:
         )
         return await self._repo.create(entity)
 
-    async def get(self, leave_wish_id: UUID) -> LeaveWish:
+    async def get(self, leave_wish_id: UUID, workspace_id: UUID | None = None) -> LeaveWish:
+        """`workspace_id`, when given, must match the entity's own — callers
+        that already know the caller's tenant (routers) pass it so a foreign
+        workspace's wish 404s exactly like a nonexistent one; internal
+        callers that don't need that check (e.g. `update`'s own re-reads
+        with no tenant context) leave it `None`.
+        """
         entity = await self._repo.get_by_id(leave_wish_id)
-        if entity is None:
+        if entity is None or (workspace_id is not None and entity.workspace_id != workspace_id):
             raise NotFoundError(f"LeaveWish {leave_wish_id} not found")
         return entity
 
@@ -101,6 +107,7 @@ class LeaveWishService:
     async def update(
         self,
         leave_wish_id: UUID,
+        workspace_id: UUID | None = None,
         child_id: UUID | None = None,
         name: str | None = None,
         name_message_key: str | None = None,
@@ -138,7 +145,7 @@ class LeaveWishService:
         `_clear_target_days` resets a day-granular wish back to being sized
         by `target_weeks` alone.
         """
-        entity = await self.get(leave_wish_id)
+        entity = await self.get(leave_wish_id, workspace_id)
         original_name = entity.name
 
         if _clear_child_id:
@@ -202,7 +209,7 @@ class LeaveWishService:
         )
         return await self._repo.update(leave_wish_id, entity)
 
-    async def delete(self, leave_wish_id: UUID) -> None:
+    async def delete(self, leave_wish_id: UUID, workspace_id: UUID | None = None) -> None:
         """Delete a wish and every `planned_leave_day` row it produced.
 
         Under the calendar-direct-manipulation UX a period *is* its wish: the
@@ -224,7 +231,7 @@ class LeaveWishService:
         deletes every day in the band regardless of `is_pinned` with no
         special-casing.
         """
-        await self.get(leave_wish_id)  # raises NotFoundError if missing
+        await self.get(leave_wish_id, workspace_id)  # raises NotFoundError if missing/foreign
         await self._planned_leave_repo.delete_by_wish(leave_wish_id)
         await self._repo.delete(leave_wish_id)