refactor(call-omo-agent): split tools.ts into agent execution modules

Extract agent call pipeline:
- agent-type-normalizer.ts, tool-context-with-metadata.ts
- subagent-session-creator.ts, subagent-session-prompter.ts
- sync-agent-executor.ts, background-agent-executor.ts
- session-completion-poller.ts, session-message-output-extractor.ts
- message-storage-directory.ts

src/tools/call-omo-agent/tool-context-with-metadata.ts

@@ -0,0 +1,10 @@
+export type ToolContextWithMetadata = {
+	sessionID: string
+	messageID: string
+	agent: string
+	abort: AbortSignal
+	metadata?: (input: {
+		title?: string
+		metadata?: Record<string, unknown>
+	}) => void
+}