#19998: macOS: harden cron editor updates and compatibility

## Summary - harden macOS cron model decoding to preserve unknown/future enum values for `sessionTarget`, `wakeMode`, and `delivery.mode` - make cron editor updates non-lossy by sending diff-only `cron.update` patches instead of full overwrites - add compatibility fallback for `postRun`-only jobs so wake behavior still decodes safely - extend editor UI to handle webhook delivery and preserve unknown/raw delivery modes - add tests covering non-clobbering edit behavior and unknown/postRun decode compatibility ## Why Current edit flow can unintentionally clobber fields introduced by other cron PRs (for example webhook/raw delivery, custom session targets, or postRun-based jobs). This change makes edit operations resilient and merge-friendly. ## Testing - `swift test --filter Cron` (from `apps/macos`) was attempted - blocked in this environment by upstream dependency macro plugin resolution in `swiftui-math` (`SwiftUIMacros` / `PreviewsMacros` not found) - added targeted unit coverage in: - `apps/macos/Tests/OpenClawIPCTests/CronJobEditorSmokeTests.swift` - `apps/macos/Tests/OpenClawIPCTests/CronModelsTests.swift` <!-- greptile_comment --> <h3>Greptile Summary</h3> This PR hardens macOS cron job editing to be non-lossy and forward-compatible. The three main changes are: - **Enum hardening**: `CronSessionTarget`, `CronWakeMode`, and `CronDeliveryMode` are refactored from raw-value enums to manual `Codable` types with `.unknown(String)` catch-all cases, preserving unrecognized values during decode/re-encode round-trips. - **Diff-only patches**: The editor now computes a JSON diff between the current job state and the edited state, sending only changed fields via `cron.update` instead of full overwrites. This prevents clobbering fields set by other cron PRs (e.g., webhook delivery, custom session targets). - **Backward compatibility**: A `postRun` fallback in the `CronJob` decoder maps legacy `"trigger-heartbeat"` values to `.nextHeartbeat`, and the UI gracefully handles webhook, raw, and unknown delivery modes. The implementation is well-structured with targeted test coverage. One concern: delivery settings are visible in the UI for non-isolated session targets (e.g., `current`) but silently excluded from the payload — this could confuse users who configure delivery for a `current`-target job. <h3>Confidence Score: 4/5</h3> - This PR is safe to merge with minor UI/UX concern around delivery visibility for non-isolated session targets. - The code changes are well-structured, the diff-only patching logic is correct, and backward-compatibility is properly handled. The enum hardening pattern is clean and idiomatic. The only concern is a UI/logic mismatch where delivery settings are editable but silently dropped for non-isolated targets. Tests cover the key scenarios but could not be run in CI due to dependency issues. - `apps/macos/Sources/OpenClaw/CronJobEditor+Helpers.swift` — delivery gating logic in `shouldIncludeDeliveryInRoot()` may silently discard user-configured delivery for non-isolated session targets. _{Last reviewed commit: 109f947} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->