Add attachment management CRUD to the /uploads API

Complete the read and update faces of the signed-in user's attachment
management over the existing attachments table:

- GET /uploads: paginated list of the user's own attachments, newest
  first, with an optional linked/orphaned filter
- GET /uploads/{uid}: fetch one attachment (owner or admin)
- PATCH /uploads/{uid}: rename the display filename, always preserving
  the original extension (owner or admin, audited as attachment.rename)

Adds get_user_attachments/get_user_attachment data helpers, the
rename_attachment operation, AttachmentRenameForm, the UploadItemOut and
UploadsListOut schemas, the Devii tools list_attachments/get_attachment/
rename_attachment, expanded API reference documentation for the full
lifecycle including delete, and api-tier tests.

devplacepy/schemas/__init__.py

@@ -115,6 +115,10 @@ from devplacepy.schemas.gateway import (
     GatewayUsageOut,
     UserAiUsageOut,
 )
+from devplacepy.schemas.uploads import (
+    UploadItemOut,
+    UploadsListOut,
+)
 from devplacepy.schemas.statistics import StatisticsOut
 from devplacepy.schemas.auth import (
     AuthPageOut,

devplacepy/schemas/uploads.py

@@ -0,0 +1,20 @@
+# retoor <retoor@molodetz.nl>
+
+from __future__ import annotations
+
+from typing import Any, Optional
+
+from devplacepy.schemas.base import _Out
+from devplacepy.schemas.profile import MediaItemOut
+
+
+class UploadItemOut(MediaItemOut):
+    is_audio: bool = False
+    linked: bool = False
+    user_uid: Optional[str] = None
+
+
+class UploadsListOut(_Out):
+    attachments: list[UploadItemOut] = []
+    pagination: Optional[Any] = None
+    total: int = 0