fix(threads): unify wait-state ownership across thread types

`hasUnresolvedWaitStatesForAgent` only joined through tasks, so
approval-only threads and ad-hoc threads where the agent is the
requesting party or an explicit participant were invisible. Result:
the heartbeat scheduler silently resumed agents that the board had
asked to wait on, Co-Founder approval chains deadlocked on the
agent side, and any new gate that relies on the query inherits the
same hole.

Root-fix the query at the SQL layer. `hasUnresolvedWaitStateForAgent`
now returns true when any of the three ownership predicates hold:

  - task thread whose task.assignee_agent_id = agent
  - approval thread whose approval.requested_by_agent_id = agent
  - any thread on which the agent is a recorded participant

Each branch is an EXISTS subquery so the query short-circuits on
first match. The thread-integration helper delegates here so the
heartbeat scheduler and the `beforeToolCall` gate share one source
of truth rather than reimplementing half-policies in parallel.

src/main/database.ts

@@ -165,6 +165,7 @@ export class AppDatabase extends AppDatabaseBase {
   setThreadWaitState(input: Parameters<ReturnType<typeof buildThreadMethods>["setThreadWaitState"]>[0]) { return this.threads.setThreadWaitState(input); }
   resolveThreadWaitState(waitStateId: string, companyId: string) { return this.threads.resolveThreadWaitState(waitStateId, companyId); }
   listThreadWaitStates(companyId: string, options?: Parameters<ReturnType<typeof buildThreadMethods>["listThreadWaitStates"]>[1]) { return this.threads.listThreadWaitStates(companyId, options); }
+  hasUnresolvedWaitStateForAgent(companyId: string, agentId: string) { return this.threads.hasUnresolvedWaitStateForAgent(companyId, agentId); }
   addParticipant(input: Parameters<ReturnType<typeof buildThreadMethods>["addParticipant"]>[0]) { return this.threads.addParticipant(input); }
   listParticipants(threadId: string) { return this.threads.listParticipants(threadId); }
   removeParticipant(threadId: string, participantId: string) { return this.threads.removeParticipant(threadId, participantId); }