feat(task): refactor to Claude Code style individual tools

- Split unified Task tool into individual tools (TaskCreate, TaskGet, TaskList, TaskUpdate)
- Update schema to Claude Code field names (subject, blockedBy, blocks, activeForm, owner, metadata)
- Add OpenCode Todo API sync layer (todo-sync.ts)
- Implement Todo sync on task create/update for continuation enforcement
- Add comprehensive tests for all tools (96 tests total)
- Update AGENTS.md documentation

Breaking Changes:
- Field names changed: title→subject, dependsOn→blockedBy, open→pending
- Tool names changed: task→task_create, task_get, task_list, task_update

Closes: todo-continuation-enforcer now sees Task-created items

src/features/claude-tasks/AGENTS.md

@@ -22,21 +22,33 @@ type TaskStatus = "pending" | "in_progress" | "completed" | "deleted"
 
 interface Task {
   id: string
-  subject: string           // Imperative: "Run tests"
+  subject: string           // Imperative: "Run tests" (was: title)
   description: string
   status: TaskStatus
   activeForm?: string       // Present continuous: "Running tests"
   blocks: string[]          // Task IDs this task blocks
-  blockedBy: string[]       // Task IDs blocking this task
+  blockedBy: string[]       // Task IDs blocking this task (was: dependsOn)
   owner?: string            // Agent name
   metadata?: Record<string, unknown>
+  repoURL?: string          // oh-my-opencode specific
+  parentID?: string         // oh-my-opencode specific
+  threadID: string          // oh-my-opencode specific
 }
 ```
 
 **Key Differences from Legacy**:
 - `subject` (was `title`)
 - `blockedBy` (was `dependsOn`)
-- No `parentID`, `repoURL`, `threadID` fields
+- `blocks` (new field)
+- `activeForm` (new field)
+
+## TODO SYNC
+
+The task system includes a sync layer (`todo-sync.ts`) that automatically mirrors task state to the project's Todo system.
+
+- **Creation**: Creating a task via `task_create` adds a corresponding item to the Todo list.
+- **Updates**: Updating a task's `status` or `subject` via `task_update` reflects in the Todo list.
+- **Completion**: Marking a task as `completed` automatically marks the Todo item as done.
 
 ## STORAGE UTILITIES