feat(checkout): merge PR action with real-GitHub e2e test (#814)

* feat(checkout): merge PR action with real-GitHub e2e test

Adds a `checkoutPrMerge` server RPC backed by `gh pr merge` (squash, merge,
or rebase) and surfaces three new actions in the git-actions menu —
"Squash and merge", "Create a merge commit", "Rebase and merge" — with
squash taking the primary slot when a PR is open and mergeable. Also
renames the existing local merge action to "Merge locally" to disambiguate
it from the new GitHub-side merge.

Adds an end-to-end test that creates a real temporary GitHub repo, opens a
PR via the daemon, polls until mergeable, calls `checkoutPrMerge`, and
verifies the merge landed on `main` — no mocks. The test pre-flights the
`delete_repo` scope so it skips cleanly on tokens that can't tear down,
and fails loud if cleanup ever errors so we don't leak repos.

PR status gains an optional `mergeable` field (`MERGEABLE | CONFLICTING |
UNKNOWN`) populated from `gh pr view --json mergeable`. The schema is
backward compatible — old payloads without the field still parse and
default to `UNKNOWN` via `z.catch`.

* Update PR status snapshot expectations

* refactor: collect git/checkout/PR feature into packages/app/src/git/

Move 21 git/checkout/PR files out of components/, hooks/, stores/, screens/,
utils/ flat-peer slop into a single packages/app/src/git/ module with
shrunk filenames (git-diff-pane.tsx -> diff-pane.tsx, use-git-actions.ts ->
use-actions.ts, etc).

Dedupe: drop the duplicate useGitActionHandlers from diff-pane.tsx — the
shared useGitActions hook is the single source. Drop the
buildGitActionsForPane wrapper. Collapse the merge-PR triple fan-out
(mergePrSquash/Merge/RebaseStatus) into one record keyed by
CheckoutPrMergeMethod. Streamline server-side single-use helpers
(dispatchStash/PullRequestMessage adapters, GitHubPullRequestMergeError
wrapper, legacy worktree test helpers).

Schema-additive only: messages.ts exports CheckoutPrMergeMethod and
PullRequestMergeable types; daemon-client.ts uses the typed alias.
Backward-compatible.

Net delta: 43 files, +219/-1212.

* fix(app): use GitHub icon for all merge-PR menu actions

* test: namespace temp GitHub repos under `paseotmp-` and centralize naming

Old prefixes (`paseo-checkout-ship-`, `paseo-e2e-`, `paseo-checkout-pr-merge-`)
collided with the `paseo-*` namespace of real repos, making bulk cleanup
unsafe. Switch every test that creates real GitHub repos to a single
unmistakable `paseotmp-` prefix, owned by one shared helper per test
boundary so no caller can name a repo outside the namespace.

- New `packages/server/src/server/test-utils/temp-github-repo.ts` exports
  `TEMP_GITHUB_REPO_PREFIX` + `createTempGithubRepoName(category)`; both
  server e2e tests (checkout-ship, checkout-pr-merge) consume it.
- `packages/app/e2e/helpers/github-fixtures.ts` locks the prefix internally
  and now requires callers to pass a `category` instead of an arbitrary
  `prefix`. Updated pr-pane and composer-attachments specs accordingly.

packages/app/src/git/workspace-actions.tsx

@@ -0,0 +1,58 @@
+import { withUnistyles } from "react-native-unistyles";
+import {
+  Archive,
+  ArrowDownUp,
+  Download,
+  GitCommitHorizontal,
+  GitMerge,
+  RefreshCcw,
+  Upload,
+} from "lucide-react-native";
+import { GitHubIcon } from "@/components/icons/github-icon";
+import { GitActionsSplitButton } from "@/git/actions-split-button";
+import { useGitActions } from "@/git/use-actions";
+import type { Theme } from "@/styles/theme";
+
+interface WorkspaceGitActionsProps {
+  serverId: string;
+  cwd: string;
+  hideLabels?: boolean;
+}
+
+const ThemedGitCommitHorizontal = withUnistyles(GitCommitHorizontal);
+const ThemedDownload = withUnistyles(Download);
+const ThemedUpload = withUnistyles(Upload);
+const ThemedArrowDownUp = withUnistyles(ArrowDownUp);
+const ThemedGitHubIcon = withUnistyles(GitHubIcon);
+const ThemedGitMerge = withUnistyles(GitMerge);
+const ThemedRefreshCcw = withUnistyles(RefreshCcw);
+const ThemedArchive = withUnistyles(Archive);
+
+const mutedColorMapping = (theme: Theme) => ({
+  color: theme.colors.foregroundMuted,
+});
+
+const ICONS = {
+  commit: <ThemedGitCommitHorizontal size={16} uniProps={mutedColorMapping} />,
+  pull: <ThemedDownload size={16} uniProps={mutedColorMapping} />,
+  push: <ThemedUpload size={16} uniProps={mutedColorMapping} />,
+  pullAndPush: <ThemedArrowDownUp size={16} uniProps={mutedColorMapping} />,
+  viewPr: <ThemedGitHubIcon size={16} uniProps={mutedColorMapping} />,
+  createPr: <ThemedGitHubIcon size={16} uniProps={mutedColorMapping} />,
+  mergePrSquash: <ThemedGitHubIcon size={16} uniProps={mutedColorMapping} />,
+  mergePrMerge: <ThemedGitHubIcon size={16} uniProps={mutedColorMapping} />,
+  mergePrRebase: <ThemedGitHubIcon size={16} uniProps={mutedColorMapping} />,
+  merge: <ThemedGitMerge size={16} uniProps={mutedColorMapping} />,
+  mergeFromBase: <ThemedRefreshCcw size={16} uniProps={mutedColorMapping} />,
+  archive: <ThemedArchive size={16} uniProps={mutedColorMapping} />,
+};
+
+export function WorkspaceGitActions({ serverId, cwd, hideLabels }: WorkspaceGitActionsProps) {
+  const { gitActions, isGit } = useGitActions({ serverId, cwd, icons: ICONS });
+
+  if (!isGit) {
+    return null;
+  }
+
+  return <GitActionsSplitButton gitActions={gitActions} hideLabels={hideLabels} />;
+}