feat(imap): add ImapIngestionProfile model, API, migration and UI

Replaces the simple binary attachment_filter string with a full
ingestion profiles system:

- Add FILE_TYPE_CATEGORIES dict to allowed_types.py (6 categories:
  pdf, office, opendocument, text, web, images) + DEFAULT_CATEGORIES
  / ALL_CATEGORIES + get_allowed_types_for_categories() helper
- Add ImapIngestionProfile model (id, name, description, owner_id,
  allowed_categories JSON, is_builtin)
- Update UserImapAccount: replace attachment_filter string with
  profile_id FK to imap_ingestion_profiles
- Migration 033: creates profiles table, seeds 2 built-in profiles
  (Documents Only, All Files), migrates attachment_filter → profile_id
- New /api/imap-profiles/ CRUD endpoints (list, create, get, update,
  delete) with category validation
- Register imap_profiles router in app/api/__init__.py
- Update imap_tasks.py: replace attachment_filter string param with
  profile-based allowed_categories; add _resolve_categories_for_profile()
- Update imap_accounts.py API to use profile_id instead of attachment_filter
- Update imap_accounts view to pass profiles + categories to template
- Full UI overhaul: profiles panel + profile create/edit modal with
  category checkboxes; profile selector in account modal
- 17 new tests (141 total), all passing

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/api/imap_accounts.py

@@ -110,12 +110,10 @@ class ImapAccountCreate(BaseModel):
     use_ssl: bool = Field(default=True, description="Use SSL/TLS connection")
     delete_after_process: bool = Field(default=False, description="Delete emails from mailbox after processing")
     is_active: bool = Field(default=True, description="Whether to poll this mailbox")
-    attachment_filter: str | None = Field(
+    profile_id: int | None = Field(
         default=None,
         description=(
-            "Controls which attachment types to ingest. "
-            "'documents_only' – PDFs and office files only (default when None). "
-            "'all' – all supported types including images. "
+            "ID of the ImapIngestionProfile that controls which attachment types to ingest. "
             "Null inherits the global imap_attachment_filter setting."
         ),
     )
@@ -132,13 +130,11 @@ class ImapAccountUpdate(BaseModel):
     use_ssl: bool | None = None
     delete_after_process: bool | None = None
     is_active: bool | None = None
-    attachment_filter: str | None = Field(
+    profile_id: int | None = Field(
         default=None,
         description=(
-            "Controls which attachment types to ingest. "
-            "'documents_only' – PDFs and office files only. "
-            "'all' – all supported types including images. "
-            "Null or empty string clears the override (inherits global setting)."
+            "ID of the ImapIngestionProfile to use.  "
+            "Explicitly sending null clears the override (falls back to global setting)."
         ),
     )
 
@@ -173,7 +169,7 @@ def _to_response(acct: UserImapAccount) -> dict[str, Any]:
         "use_ssl": acct.use_ssl,
         "delete_after_process": acct.delete_after_process,
         "is_active": acct.is_active,
-        "attachment_filter": acct.attachment_filter,
+        "profile_id": acct.profile_id,
         "last_checked_at": acct.last_checked_at.isoformat() if acct.last_checked_at else None,
         "last_error": acct.last_error,
         "created_at": acct.created_at.isoformat() if acct.created_at else None,
@@ -241,7 +237,7 @@ def create_imap_account(
         use_ssl=body.use_ssl,
         delete_after_process=body.delete_after_process,
         is_active=body.is_active,
-        attachment_filter=body.attachment_filter or None,
+        profile_id=body.profile_id,
     )
     try:
         db.add(acct)
@@ -297,12 +293,10 @@ def update_imap_account(
         acct.delete_after_process = body.delete_after_process
     if body.is_active is not None:
         acct.is_active = body.is_active
-    # attachment_filter uses a sentinel check: the field is always present in the
-    # model (defaulting to None in Pydantic) so we update it unconditionally when
-    # the caller sends any value (including explicit null to clear the override).
-    # An empty string is normalised to None to avoid storing a non-meaningful value.
-    if "attachment_filter" in body.model_fields_set:
-        acct.attachment_filter = body.attachment_filter or None
+    # profile_id: update whenever the field is explicitly present in the request payload
+    # (including sending null to clear the override).
+    if "profile_id" in body.model_fields_set:
+        acct.profile_id = body.profile_id
 
     # Reset last_error so the next poll gives a fresh result
     acct.last_error = None