* fix(ui): enable save button only when config has changes
The save button in the Control UI config editor was not properly gating
on whether actual changes were made. This adds:
- `configRawOriginal` state to track the original raw config for comparison
- Change detection for both form mode (via computeDiff) and raw mode
- `hasChanges` check in canSave/canApply logic
- Set `configFormDirty` when raw mode edits occur
- Handle raw mode UI correctly (badge shows "Unsaved changes", no diff panel)
Fixes#1609
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* feat(gateway-tool): add config.patch action for safe partial config updates
Exposes the existing config.patch server method to agents, allowing safe
partial config updates that merge with existing config instead of replacing it.
- Add config.patch to GATEWAY_ACTIONS in gateway tool
- Add restart + sentinel logic to config.patch server method
- Extend ConfigPatchParamsSchema with sessionKey, note, restartDelayMs
- Add unit test for config.patch gateway tool action
Closes#1617
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Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
