calendar: fix stale docs and remove unnecessary METHOD from todo add

- Remove duplicate email rule in TOOLS.md
- Add todo mutations to sync description in TOOLS.md
- Remove METHOD:REQUEST from todo add ICS (no longer emailed)
- Update todo check description in SKILL.md

skills/calendar/scripts/cal_tool.py

@@ -479,7 +479,6 @@ def cmd_todo_add(args):
     cal = Calendar()
     cal.add("prodid", PRODID)
     cal.add("version", "2.0")
-    cal.add("method", "REQUEST")
 
     todo = Todo()
     todo.add("uid", uid)
@@ -510,9 +509,9 @@ def cmd_todo_add(args):
         print(ics_bytes.decode())
         return
 
-    # Save to TASKS_DIR (without METHOD for CalDAV)
+    # Save to TASKS_DIR
     dest = TASKS_DIR / f"{uid}.ics"
-    dest.write_bytes(_strip_method(ics_bytes))
+    dest.write_bytes(ics_bytes)
     print(f"Todo created: {args.summary} (due: {due_date}, priority: {prio_label})")
     print(f"Saved to: {dest}")