fix(6229): remove the Profile settings page — nothing read it

The Profile tab said an assistant used it to personalise chat and a daily
journal. Neither exists, and nothing read the profile: the page saved to
user_profiles and the backup carried it. Removed the tab, the client calls,
/api/profile, the service and the model, and migration 0123 drops the table
(downgrade recreates it empty).

Backup format v27 stops writing user_profiles; an older archive carrying the
section still restores, and the file-restore integration test now proves it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_services_backup.py

@@ -21,11 +21,8 @@ from scribe.services import backup
 def test_backup_version_is_current():
     """The bump is the point of the test — a payload section added without
     moving the version produces backups that are structurally different and
-    indistinguishable by inspection.
-
-    (Named for the number it asserted until v10, which is exactly the drift a
-    name-carrying-a-value invites; it now says what it checks.)"""
-    assert backup.BACKUP_VERSION == 26
+    indistinguishable by inspection."""
+    assert backup.BACKUP_VERSION == 27
 
 
 def _exportable_note(**over):
@@ -164,7 +161,6 @@ def _column_guard_targets():
     from scribe.models.system import RecordSystem, System
     from scribe.models.task_log import TaskLog
     from scribe.models.user import User
-    from scribe.models.user_profile import UserProfile
 
     return {
         "users": (User, backup._user_rows),
@@ -212,7 +208,6 @@ def _column_guard_targets():
         "family_idea_references": (FamilyIdeaReference, backup._family_idea_reference_rows),
         "family_adoptions": (FamilyAdoption, backup._family_adoption_rows),
         "family_decisions": (FamilyDecision, backup._family_decision_rows),
-        "user_profiles": (UserProfile, backup._user_profile_rows),
     }
 
 
@@ -324,7 +319,6 @@ def _import_guard_targets():
         "system_usage_events": backup._build_system_usage_event,
         "retrieval_tuning_events": backup._build_retrieval_tuning_event,
         "moment_mappings": backup._build_moment_mapping,
-        "user_profiles": backup._build_user_profile,
         "design_systems": backup._build_design_system,
         "design_tokens": backup._build_design_token,
         "repo_bindings": backup._build_repo_binding,
@@ -593,9 +587,7 @@ async def test_export_full_backup_contains_every_declared_section():
                 # v25: family canon.
                 "platforms", "project_platforms", "family_ideas",
                 "family_idea_platforms", "family_idea_references",
-                "family_adoptions", "family_decisions",
-                # v26: the Profile page.
-                "user_profiles"):
+                "family_adoptions", "family_decisions"):
         assert key in out, f"missing export section: {key}"
         assert out[key] == []