Add manual refresh button to git diff controls (#1216)

* feat(git): add manual refresh button to diff controls

Adds a checkout_refresh RPC that forces a hard re-read of the git and
GitHub snapshot plus the diff, bypassing polling. The diff controls now
show a refresh button (feature-gated) that triggers it and surfaces
errors via a toast — an escape hatch when the polled state goes stale.

* refactor(git): address review — dotted RPC name + withUnistyles

- Rename checkout_refresh RPC to the dotted convention
  (checkout.refresh.request/response) per docs/rpc-namespacing.md.
- Replace the banned useUnistyles() call in DiffRefreshButton with
  withUnistyles wrappers for the icon/spinner color, per docs/unistyles.md.

* refactor(git): move refresh into the checkout actions store

Per the feature audit: the manual refresh was the one checkout action
whose UI logic lived inline in the component instead of alongside its
siblings (commit/pull/push) in useCheckoutGitActionsStore. Move it into
the store so there's one home for "UI triggers a checkout RPC" — it now
reuses runCheckoutAction's pending/success status and query invalidation.
The component just reads status and shows an error toast.

* fix(git): size refresh loader to the icon to stop layout shift

ActivityIndicator size="small" renders ~20px regardless of platform,
wider than the 14px refresh icon, so swapping to it grew the button and
shifted the controls row. Use SyncedLoader at the same iconSize — it
renders into a size×size box, so both states share one footprint.

* fix(git): match file-explorer refresh control (RotateCw + LoadingSpinner)

Mirror the file-explorer pane's refresh button exactly: RotateCw icon,
LoadingSpinner while refreshing, both centered in a fixed icon-sized box
so the spinner can't grow the control or shift the row. Replaces the
ad-hoc RefreshCw + SyncedLoader pairing.

packages/client/src/daemon-client.ts

@@ -31,6 +31,7 @@ import type {
   CheckoutMergeFromBaseResponse,
   CheckoutPullResponse,
   CheckoutPushResponse,
+  CheckoutRefreshResponse,
   CheckoutPrCreateResponse,
   CheckoutPrMergeResponse,
   CheckoutPrMergeMethod,
@@ -288,6 +289,7 @@ type CheckoutMergePayload = CheckoutMergeResponse["payload"];
 type CheckoutMergeFromBasePayload = CheckoutMergeFromBaseResponse["payload"];
 type CheckoutPullPayload = CheckoutPullResponse["payload"];
 type CheckoutPushPayload = CheckoutPushResponse["payload"];
+type CheckoutRefreshPayload = CheckoutRefreshResponse["payload"];
 type CheckoutPrCreatePayload = CheckoutPrCreateResponse["payload"];
 type CheckoutPrMergePayload = CheckoutPrMergeResponse["payload"];
 type CheckoutGithubSetAutoMergePayload = CheckoutGithubSetAutoMergeResponse["payload"];
@@ -2950,6 +2952,18 @@ export class DaemonClient {
     });
   }
 
+  async checkoutRefresh(cwd: string, requestId?: string): Promise<CheckoutRefreshPayload> {
+    return this.sendCorrelatedSessionRequest({
+      requestId,
+      message: {
+        type: "checkout.refresh.request",
+        cwd,
+      },
+      responseType: "checkout.refresh.response",
+      timeout: 60000,
+    });
+  }
+
   async checkoutPrCreate(
     cwd: string,
     input: { title?: string; body?: string; baseRef?: string },