feat: implement work heartbeat service for health checks and task dispatching

- Introduced a new heartbeat service that runs at defined intervals to perform health checks on workers and fill available task slots based on priority.
- Added a health tool to scan worker health across projects with optional auto-fix capabilities.
- Updated the status tool to provide a lightweight overview of worker states and queue counts without health checks.
- Enhanced task creation tool descriptions to clarify task state handling.
- Implemented tests for the work heartbeat logic, ensuring proper project resolution, worker state management, and task prioritization.

lib/templates.ts

@@ -26,7 +26,7 @@ Read the comments carefully — they often contain clarifications, decisions, or
 - Clean up the worktree after merging
 - When done, call work_finish with role "dev", result "done", and a brief summary
 - If you discover unrelated bugs, call task_create to file them
-- Do NOT call work_start, status, or project_register
+- Do NOT call work_start, status, health, work_heartbeat, or project_register
 `;
 
 export const DEFAULT_QA_INSTRUCTIONS = `# QA Worker Instructions
@@ -41,7 +41,7 @@ export const DEFAULT_QA_INSTRUCTIONS = `# QA Worker Instructions
   - result "fail" with specific issues if problems found
   - result "refine" if you need human input to decide
 - If you discover unrelated bugs, call task_create to file them
-- Do NOT call work_start, status, or project_register
+- Do NOT call work_start, status, health, work_heartbeat, or project_register
 `;
 
 export const AGENTS_MD_TEMPLATE = `# AGENTS.md - Development Orchestration (DevClaw)
@@ -82,7 +82,7 @@ If you discover unrelated bugs or needed improvements during your work, call \`t
 ### Tools You Should NOT Use
 
 These are orchestrator-only tools. Do not call them:
-- \`work_start\`, \`status\`, \`auto_pickup\`, \`project_register\`
+- \`work_start\`, \`status\`, \`health\`, \`work_heartbeat\`, \`project_register\`
 
 ---
 
@@ -99,7 +99,8 @@ All orchestration goes through these tools. You do NOT manually manage sessions,
 | \`project_register\` | One-time project setup: creates labels, scaffolds role files, adds to projects.json |
 | \`task_create\` | Create issues from chat (bugs, features, tasks) |
 | \`task_update\` | Update issue title, description, or labels |
-| \`status\` | Scans issue queue + worker state + health checks |
+| \`status\` | Task queue and worker state per project (lightweight dashboard) |
+| \`health\` | Scan worker health: zombies, stale workers, orphaned state. Pass fix=true to auto-fix |
 | \`work_start\` | End-to-end: label transition, tier assignment, session create/reuse, dispatch with role instructions |
 | \`work_finish\` | End-to-end: label transition, state update, issue close/reopen. Auto-ticks queue after completion. |
 
@@ -149,7 +150,7 @@ Workers receive role-specific instructions appended to their task message. These
 
 ### Heartbeats
 
-On heartbeat, call \`auto_pickup\` — it runs health checks and picks up available work automatically.
+**Do nothing.** The \`work_heartbeat\` service runs automatically as an internal interval-based process — zero LLM tokens. It handles health checks (zombie detection, stale workers) and queue dispatch (filling free worker slots by priority) every 60 seconds by default. Configure via \`plugins.entries.devclaw.config.work_heartbeat\` in openclaw.json.
 
 ### Safety
 
@@ -161,15 +162,5 @@ On heartbeat, call \`auto_pickup\` — it runs health checks and picks up availa
 
 export const HEARTBEAT_MD_TEMPLATE = `# HEARTBEAT.md
 
-On each heartbeat, call \`auto_pickup\` (no parameters needed for a full sweep).
-
-It will automatically:
-1. Run health checks (zombie workers, stale sessions)
-2. Scan queues across all projects
-3. Pick up available work by priority: To Improve > To Test > To Do
-4. Choose appropriate developer tier based on task complexity
-
-If you want to target a single project, pass \`projectGroupId\`.
-
-If nothing needs attention, it reports HEARTBEAT_OK.
+Do nothing. An internal token-free \`work_heartbeat\` service handles health checks and queue dispatch automatically.
 `;