fix: address 8-domain Oracle review findings (C1, C2, M1-M4)

- C1: thinking-prepend unique part IDs per message (global PK collision)
- C2: recover-thinking-disabled-violation try/catch guard on SDK call
- M1: remove non-schema truncated/originalSize fields from SDK interfaces
- M2: messageHasContentFromSDK treats thinking-only messages as non-empty
- M3: syncAllTasksToTodos persists finalTodos + no-id rename dedup guard
- M4: AbortSignal.timeout(30s) on HTTP fetch calls in opencode-http-api

All 2739 tests pass, typecheck clean.

src/tools/task/todo-sync.test.ts

@@ -418,12 +418,16 @@ describe("syncAllTasksToTodos", () => {
       },
     ];
     mockCtx.client.session.todo.mockResolvedValue(currentTodos);
+    let writtenTodos: TodoInfo[] = [];
+    const writer = async (input: { sessionID: string; todos: TodoInfo[] }) => {
+      writtenTodos = input.todos;
+    };
 
     // when
-    await syncAllTasksToTodos(mockCtx, tasks, "session-1");
+    await syncAllTasksToTodos(mockCtx, tasks, "session-1", writer);
 
     // then
-    expect(mockCtx.client.session.todo).toHaveBeenCalled();
+    expect(writtenTodos.some((t: TodoInfo) => t.id === "T-1")).toBe(false);
   });
 
   it("preserves existing todos not in task list", async () => {
@@ -451,12 +455,17 @@ describe("syncAllTasksToTodos", () => {
       },
     ];
     mockCtx.client.session.todo.mockResolvedValue(currentTodos);
+    let writtenTodos: TodoInfo[] = [];
+    const writer = async (input: { sessionID: string; todos: TodoInfo[] }) => {
+      writtenTodos = input.todos;
+    };
 
     // when
-    await syncAllTasksToTodos(mockCtx, tasks, "session-1");
+    await syncAllTasksToTodos(mockCtx, tasks, "session-1", writer);
 
     // then
-    expect(mockCtx.client.session.todo).toHaveBeenCalled();
+    expect(writtenTodos.some((t: TodoInfo) => t.id === "T-existing")).toBe(true);
+    expect(writtenTodos.some((t: TodoInfo) => t.content === "Task 1")).toBe(true);
   });
 
   it("handles empty task list", async () => {
@@ -471,6 +480,67 @@ describe("syncAllTasksToTodos", () => {
     expect(mockCtx.client.session.todo).toHaveBeenCalled();
   });
 
+  it("calls writer with final todos", async () => {
+    // given
+    const tasks: Task[] = [
+      {
+        id: "T-1",
+        subject: "Task 1",
+        description: "Description 1",
+        status: "pending",
+        blocks: [],
+        blockedBy: [],
+      },
+    ];
+    mockCtx.client.session.todo.mockResolvedValue([]);
+    let writerCalled = false;
+    const writer = async (input: { sessionID: string; todos: TodoInfo[] }) => {
+      writerCalled = true;
+      expect(input.sessionID).toBe("session-1");
+      expect(input.todos.length).toBe(1);
+      expect(input.todos[0].content).toBe("Task 1");
+    };
+
+    // when
+    await syncAllTasksToTodos(mockCtx, tasks, "session-1", writer);
+
+    // then
+    expect(writerCalled).toBe(true);
+  });
+
+  it("deduplicates no-id todos when task replaces existing content", async () => {
+    // given
+    const tasks: Task[] = [
+      {
+        id: "T-1",
+        subject: "Task 1 (updated)",
+        description: "Description 1",
+        status: "in_progress",
+        blocks: [],
+        blockedBy: [],
+      },
+    ];
+    const currentTodos: TodoInfo[] = [
+      {
+        content: "Task 1 (updated)",
+        status: "pending",
+      },
+    ];
+    mockCtx.client.session.todo.mockResolvedValue(currentTodos);
+    let writtenTodos: TodoInfo[] = [];
+    const writer = async (input: { sessionID: string; todos: TodoInfo[] }) => {
+      writtenTodos = input.todos;
+    };
+
+    // when
+    await syncAllTasksToTodos(mockCtx, tasks, "session-1", writer);
+
+    // then — no duplicates
+    const matching = writtenTodos.filter((t: TodoInfo) => t.content === "Task 1 (updated)");
+    expect(matching.length).toBe(1);
+    expect(matching[0].status).toBe("in_progress");
+  });
+
   it("preserves todos without id field", async () => {
     // given
     const tasks: Task[] = [

src/tools/task/todo-sync.ts

@@ -139,6 +139,7 @@ export async function syncAllTasksToTodos(
   ctx: PluginInput,
   tasks: Task[],
   sessionID?: string,
+  writer?: TodoWriter,
 ): Promise<void> {
   try {
     let currentTodos: TodoInfo[] = [];
@@ -156,8 +157,10 @@ export async function syncAllTasksToTodos(
 
     const newTodos: TodoInfo[] = [];
     const tasksToRemove = new Set<string>();
+    const allTaskSubjects = new Set<string>();
 
     for (const task of tasks) {
+      allTaskSubjects.add(task.subject);
       const todo = syncTaskToTodo(task);
       if (todo === null) {
         tasksToRemove.add(task.id);
@@ -176,13 +179,19 @@ export async function syncAllTasksToTodos(
       const isInNewTodos = newTodos.some((newTodo) => todosMatch(existing, newTodo));
       const isRemovedById = existing.id ? tasksToRemove.has(existing.id) : false;
       const isRemovedByContent = !existing.id && removedTaskSubjects.has(existing.content);
-      if (!isInNewTodos && !isRemovedById && !isRemovedByContent) {
+      const isReplacedByTask = !existing.id && allTaskSubjects.has(existing.content);
+      if (!isInNewTodos && !isRemovedById && !isRemovedByContent && !isReplacedByTask) {
         finalTodos.push(existing);
       }
     }
 
     finalTodos.push(...newTodos);
 
+    const resolvedWriter = writer ?? (await resolveTodoWriter());
+    if (resolvedWriter && sessionID) {
+      await resolvedWriter({ sessionID, todos: finalTodos });
+    }
+
     log("[todo-sync] Synced todos", {
       count: finalTodos.length,
       sessionID,