feat: add startWecker and stopWecker mutations to start/stop alarm via API

- Add startWecker mutation: starts wecker.py via subprocess if not already ringing
- Add stopWecker mutation: kills the running wecker process via SIGTERM if ringing
- Both mutations handle the 'already ringing' / 'not ringing' edge cases gracefully
- Update README with API documentation for the new mutations
- Add comprehensive tests (unit + GraphQL endpoint)

api/schema.py

@@ -2,6 +2,8 @@ import strawberry
 from typing import List, Optional
 import os
 import sys
+import subprocess
+import signal
 from pathlib import Path
 from api.crontab_manager import CrontabManager
 from common import PID_FILE
@@ -95,5 +97,36 @@ class Mutation:
             return True
         return False
 
+    @strawberry.field
+    def start_wecker(self) -> bool:
+        """Start the wecker alarm if it is not already ringing.
+        Returns True if started, False if already ringing."""
+        if is_wecker_ringing():
+            return False
+        project_root = Path(__file__).parent.parent.absolute()
+        python_exec = sys.executable
+        cmd = f"cd {project_root} && {python_exec} wecker.py >> wecker.log 2>&1"
+        subprocess.Popen(cmd, shell=True)
+        return True
+
+    @strawberry.field
+    def stop_wecker(self) -> bool:
+        """Stop the wecker alarm if it is currently ringing.
+        Returns True if stopped, False if not ringing."""
+        if not is_wecker_ringing():
+            return False
+        try:
+            with open(PID_FILE) as f:
+                pid = int(f.read().strip())
+            os.kill(pid, signal.SIGTERM)
+            if os.path.exists(PID_FILE):
+                os.remove(PID_FILE)
+            return True
+        except (ValueError, ProcessLookupError, PermissionError, OSError):
+            # PID file is stale or process already dead
+            if os.path.exists(PID_FILE):
+                os.remove(PID_FILE)
+            return False
+
 
 schema = strawberry.Schema(query=Query, mutation=Mutation)