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/subagent-session-prompter.ts

@@ -0,0 +1,26 @@
+import type { PluginInput } from "@opencode-ai/plugin"
+import { log, getAgentToolRestrictions } from "../../shared"
+
+export async function promptSubagentSession(
+	ctx: PluginInput,
+	options: { sessionID: string; agent: string; prompt: string },
+): Promise<{ ok: true } | { ok: false; error: string }> {
+	try {
+		await ctx.client.session.promptAsync({
+			path: { id: options.sessionID },
+			body: {
+				agent: options.agent,
+				tools: {
+					...getAgentToolRestrictions(options.agent),
+					task: false,
+				},
+				parts: [{ type: "text", text: options.prompt }],
+			},
+		})
+		return { ok: true }
+	} catch (error) {
+		const errorMessage = error instanceof Error ? error.message : String(error)
+		log("[call_omo_agent] Prompt error", { error: errorMessage })
+		return { ok: false, error: errorMessage }
+	}
+}