fix: schema drifts, RLS policies, wiki plugin, agent_loop syntax, test imports, frontend error handling

- Migration 0135: Fix 3 VARCHAR length drifts + 2 missing tables (forgejo_reported_errors, pgp_keys)
- Migration 0136: Fix 8 RLS policies referencing app.tenant_id instead of app.current_tenant_id
- wiki/__init__.py: Import WikiPlugin for discover_builtins()
- wiki/plugin.py: Fix SyntaxError (unterminated triple-quoted string)
- agent_loop.py: Fix SyntaxError (stray n character in dict)
- test_p1_6_dms_streaming.py: Fix import (CHUNK_SIZE removed, use _sanitize_filename only)
- conftest.py: Use create_all only (alembic conflicts with create_all in tests)
- frontend errorTypes.ts: asError() now handles nested detail objects
- AGENTS.md: Sub-agents forbidden in this project
- DAMAGE_REPORT.md + SCHEMA_DRIFTS.md: Complete damage assessment
- scripts/schema_drift_check.py: Schema drift checker tool

Tests: 24/24 Phase J + 12/12 Phase K = 36/36 passed
tsc: 0 errors
Frontend build: successful

app/plugins/builtins/wiki/__init__.py

@@ -0,0 +1,5 @@
+"""Wiki plugin — categories, articles, markdown editor, version history."""
+
+from app.plugins.builtins.wiki.plugin import WikiPlugin
+
+__all__ = ["WikiPlugin"]