fix: resolve deadlock in config handler during plugin initialization (#1304)

* fix: resolve deadlock in config handler during plugin initialization

The config handler and createBuiltinAgents were calling fetchAvailableModels
with client, which triggers client.provider.list() API call to OpenCode server.
This caused a deadlock because:
- Plugin initialization waits for server response
- Server waits for plugin init to complete before handling requests

Now using cache-only mode by passing undefined instead of client.
If cache is unavailable, the fallback chain will use the first model.

Fixes #1301

* test: add regression tests for deadlock prevention in fetchAvailableModels

Add tests to ensure fetchAvailableModels is called with undefined client
during plugin initialization. This prevents regression on issue #1301.

- config-handler.test.ts: verify config handler does not pass client
- utils.test.ts: verify createBuiltinAgents does not pass client

* test: restore spies in utils.test.ts to prevent test pollution

Add mockRestore() calls for all spies created in test cases to ensure proper cleanup between tests and prevent state leakage.

* test: restore fetchAvailableModels spy

---------

Co-authored-by: robin <robin@watcha.com>
Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>

src/plugin-handlers/config-handler.test.ts

@@ -396,3 +396,46 @@ describe("Prometheus direct override priority over category", () => {
     expect(agents.prometheus.temperature).toBe(0.1)
   })
 })
+
+describe("Deadlock prevention - fetchAvailableModels must not receive client", () => {
+  test("fetchAvailableModels should be called with undefined client to prevent deadlock during plugin init", async () => {
+    // #given - This test ensures we don't regress on issue #1301
+    // Passing client to fetchAvailableModels during config handler causes deadlock:
+    // - Plugin init waits for server response (client.provider.list())
+    // - Server waits for plugin init to complete before handling requests
+    const fetchSpy = spyOn(shared, "fetchAvailableModels" as any).mockResolvedValue(new Set<string>())
+
+    const pluginConfig: OhMyOpenCodeConfig = {
+      sisyphus_agent: {
+        planner_enabled: true,
+      },
+    }
+    const config: Record<string, unknown> = {
+      model: "anthropic/claude-opus-4-5",
+      agent: {},
+    }
+    const mockClient = {
+      provider: { list: () => Promise.resolve({ data: { connected: [] } }) },
+      model: { list: () => Promise.resolve({ data: [] }) },
+    }
+    const handler = createConfigHandler({
+      ctx: { directory: "/tmp", client: mockClient },
+      pluginConfig,
+      modelCacheState: {
+        anthropicContext1MEnabled: false,
+        modelContextLimitsCache: new Map(),
+      },
+    })
+
+    // #when
+    await handler(config)
+
+    // #then - fetchAvailableModels must be called with undefined as first argument (no client)
+    // This prevents the deadlock described in issue #1301
+    expect(fetchSpy).toHaveBeenCalled()
+    const firstCallArgs = fetchSpy.mock.calls[0]
+    expect(firstCallArgs[0]).toBeUndefined()
+
+    fetchSpy.mockRestore?.()
+  })
+})