refactor(tools/call-omo-agent): split tools.ts into focused modules under 200 LOC

- Extract getMessageDir to message-dir.ts
- Extract executeBackground to background-executor.ts
- Extract session creation logic to session-creator.ts
- Extract polling logic to completion-poller.ts
- Extract message processing to message-processor.ts
- Create sync-executor.ts to orchestrate sync execution
- Add ToolContextWithMetadata type to types.ts
- tools.ts now <200 LOC and focused on tool definition

src/tools/call-omo-agent/session-creator.ts

@@ -0,0 +1,70 @@
+import type { CallOmoAgentArgs } from "./types"
+import type { PluginInput } from "@opencode-ai/plugin"
+import { log } from "../../shared"
+
+export async function createOrGetSession(
+  args: CallOmoAgentArgs,
+  toolContext: {
+    sessionID: string
+    messageID: string
+    agent: string
+    abort: AbortSignal
+    metadata?: (input: { title?: string; metadata?: Record<string, unknown> }) => void
+  },
+  ctx: PluginInput
+): Promise<{ sessionID: string; isNew: boolean }> {
+  if (args.session_id) {
+    log(`[call_omo_agent] Using existing session: ${args.session_id}`)
+    const sessionResult = await ctx.client.session.get({
+      path: { id: args.session_id },
+    })
+    if (sessionResult.error) {
+      log(`[call_omo_agent] Session get error:`, sessionResult.error)
+      throw new Error(`Failed to get existing session: ${sessionResult.error}`)
+    }
+    return { sessionID: args.session_id, isNew: false }
+  } else {
+    log(`[call_omo_agent] Creating new session with parent: ${toolContext.sessionID}`)
+    const parentSession = await ctx.client.session.get({
+      path: { id: toolContext.sessionID },
+    }).catch((err) => {
+      log(`[call_omo_agent] Failed to get parent session:`, err)
+      return null
+    })
+    log(`[call_omo_agent] Parent session dir: ${parentSession?.data?.directory}, fallback: ${ctx.directory}`)
+    const parentDirectory = parentSession?.data?.directory ?? ctx.directory
+
+    const createResult = await ctx.client.session.create({
+      body: {
+        parentID: toolContext.sessionID,
+        title: `${args.description} (@${args.subagent_type} subagent)`,
+        permission: [
+          { permission: "question", action: "deny" as const, pattern: "*" },
+        ],
+      } as any,
+      query: {
+        directory: parentDirectory,
+      },
+    })
+
+    if (createResult.error) {
+      log(`[call_omo_agent] Session create error:`, createResult.error)
+      const errorStr = String(createResult.error)
+      if (errorStr.toLowerCase().includes("unauthorized")) {
+        throw new Error(`Failed to create session (Unauthorized). This may be due to:
+1. OAuth token restrictions (e.g., Claude Code credentials are restricted to Claude Code only)
+2. Provider authentication issues
+3. Session permission inheritance problems
+
+Try using a different provider or API key authentication.
+
+Original error: ${createResult.error}`)
+      }
+      throw new Error(`Failed to create session: ${createResult.error}`)
+    }
+
+    const sessionID = createResult.data.id
+    log(`[call_omo_agent] Created session: ${sessionID}`)
+    return { sessionID, isNew: true }
+  }
+}