fix(db): delegate get/set_full_capabilities onto DatabaseManager facade (#1200)

[dolho]

Problem

GET and PUT /api/agents/{name}/capabilities both return HTTP 500 since the #1093 SQLAlchemy-Core db decomposition (v0.6.1):

AttributeError: 'DatabaseManager' object has no attribute 'get_full_capabilities'
  File "routers/agent_config.py", line 288, in get_agent_capabilities
    db_full_caps = db.get_full_capabilities(agent_name)

get_full_capabilities / set_full_capabilities live on SecurityMixin (composed into AgentOperations, i.e. db._agent_ops) but were never given a delegating pass-through on the DatabaseManager facade the routers call. So an agent's full-capabilities setting can be neither read nor changed via API/UI. Backend-independent (pure facade gap; SQLite + PostgreSQL).

Fix

Add the two pass-throughs on DatabaseManager, alongside the existing read-only delegations (src/backend/database.py):

def get_full_capabilities(self, agent_name: str) -> bool:
    return self._agent_ops.get_full_capabilities(agent_name)

def set_full_capabilities(self, agent_name: str, enabled: bool) -> bool:
    return self._agent_ops.set_full_capabilities(agent_name, enabled)

The SecurityMixin implementations already exist — this purely restores the facade passthrough.

Tests

tests/unit/test_database_facade_delegation.py already whitelisted these two names in KNOWN_FACADE_GAPS. Removed them so the AST-based static guard now actively enforces the delegation, and added an explicit test_1200_capabilities_methods_delegated regression check.

unit/test_database_facade_delegation.py ... 3 passed
unit/test_capability_set.py             ... 4 passed

Sweep (per issue note)

Swept every method on the AgentOperations mixins for un-delegated facade gaps. Only the two capabilities methods are both missing and called as db.<m>(...). is_agent_shared_with_email is also un-delegated but has 0 db. call sites (latent, not a live 500) — left out of scope. The other KNOWN_FACADE_GAPS entries are pre-existing, unrelated to #1200.

Related to #1200. Sibling #1093 regression: #1199.

🤖 Generated with Claude Code

[github-actions]

⚠️ Nightly unit-suite check skipped — merge conflict against dev.

Resolve by running git merge dev locally and pushing the result. The next nightly run will re-test once the conflict is gone.