refactor: Rename agent modes breakdown→plan, decompose→detail

Full rename across the codebase for clarity:
- breakdown (initiative→phases) is now "plan"
- decompose (phase→tasks) is now "detail"

Updates schema enums, TypeScript types, events, prompts, output handler,
tRPC procedures, CLI commands, frontend components, tests, and docs.
Also fixes 0022 migration multi-statement issue (adds statement-breakpoint markers).

docs/dispatch-events.md

@@ -32,7 +32,7 @@
 AgentSpawnedEvent    { agentId, name, taskId, worktreeId, provider }
 AgentStoppedEvent    { agentId, name, taskId, reason }
   // reason: 'user_requested'|'task_complete'|'error'|'waiting_for_input'|
-  //         'context_complete'|'breakdown_complete'|'decompose_complete'|'refine_complete'
+  //         'context_complete'|'plan_complete'|'detail_complete'|'refine_complete'
 AgentWaitingEvent    { agentId, name, taskId, sessionId, questions[] }
 AgentOutputEvent     { agentId, stream, data }
 TaskCompletedEvent   { taskId, agentId, success, message }