feat(cron): introduce delivery modes for isolated jobs

- Added support for new delivery modes in cron jobs: `announce`, `deliver`, and `none`.
- Updated documentation to reflect changes in delivery options and usage examples.
- Enhanced the cron job schema to include delivery configuration.
- Refactored related CLI commands and UI components to accommodate the new delivery settings.
- Improved handling of legacy delivery fields for backward compatibility.

This update allows users to choose how output from isolated jobs is delivered, enhancing flexibility in job management.

src/agents/tools/cron-tool.ts

@@ -174,6 +174,7 @@ JOB SCHEMA (for add action):
   "name": "string (optional)",
   "schedule": { ... },      // Required: when to run
   "payload": { ... },       // Required: what to execute
+  "delivery": { ... },      // Optional: announce/deliver output (isolated only)
   "sessionTarget": "main" | "isolated",  // Required
   "enabled": true | false   // Optional, default true
 }
@@ -190,7 +191,13 @@ PAYLOAD TYPES (payload.kind):
 - "systemEvent": Injects text as system event into session
   { "kind": "systemEvent", "text": "<message>" }
 - "agentTurn": Runs agent with message (isolated sessions only)
-  { "kind": "agentTurn", "message": "<prompt>", "model": "<optional>", "thinking": "<optional>", "timeoutSeconds": <optional>, "deliver": <optional-bool>, "channel": "<optional>", "to": "<optional>", "bestEffortDeliver": <optional-bool> }
+  { "kind": "agentTurn", "message": "<prompt>", "model": "<optional>", "thinking": "<optional>", "timeoutSeconds": <optional> }
+
+DELIVERY (isolated-only, top-level):
+  { "mode": "none|announce|deliver", "channel": "<optional>", "to": "<optional>", "bestEffort": <optional-bool> }
+
+LEGACY DELIVERY (payload, only when delivery is omitted):
+  { "deliver": <optional-bool>, "channel": "<optional>", "to": "<optional>", "bestEffortDeliver": <optional-bool> }
 
 CRITICAL CONSTRAINTS:
 - sessionTarget="main" REQUIRES payload.kind="systemEvent"