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/use-pr-status-query.ts

@@ -0,0 +1,157 @@
+import { useQuery, useQueryClient } from "@tanstack/react-query";
+import { useEffect } from "react";
+import { useHostRuntimeClient, useHostRuntimeIsConnected } from "@/runtime/host-runtime";
+import type { CheckoutPrStatusResponse } from "@server/shared/messages";
+
+export function checkoutPrStatusQueryKey(serverId: string, cwd: string) {
+  return ["checkoutPrStatus", serverId, cwd] as const;
+}
+
+interface UseCheckoutPrStatusQueryOptions {
+  serverId: string;
+  cwd: string;
+  enabled?: boolean;
+}
+
+export type CheckoutPrStatusPayload = CheckoutPrStatusResponse["payload"];
+
+export interface PrHint {
+  url: string;
+  number: number;
+  state: "open" | "merged" | "closed";
+  checks?: Array<{ name: string; status: string; url: string | null }>;
+  checksStatus?: "none" | "pending" | "success" | "failure";
+  reviewDecision?: "approved" | "changes_requested" | "pending" | null;
+}
+
+function parsePullRequestNumber(url: string): number | null {
+  try {
+    const pathname = new URL(url).pathname;
+    const match = pathname.match(/\/pull\/(\d+)(?:\/|$)/);
+    if (!match) {
+      return null;
+    }
+
+    const number = Number.parseInt(match[1], 10);
+    return Number.isFinite(number) ? number : null;
+  } catch {
+    return null;
+  }
+}
+
+function selectWorkspacePrHint(payload: CheckoutPrStatusPayload): PrHint | null {
+  const status = payload.status;
+  if (!status?.url) {
+    return null;
+  }
+
+  const number = parsePullRequestNumber(status.url);
+  if (number === null) {
+    return null;
+  }
+
+  let state: "merged" | "open" | "closed";
+  if (status.isMerged || status.state === "merged") state = "merged";
+  else if (status.state === "open") state = "open";
+  else state = "closed";
+
+  return {
+    url: status.url,
+    number,
+    state,
+    checks: status.checks,
+    checksStatus: status.checksStatus as PrHint["checksStatus"],
+    reviewDecision: status.reviewDecision as PrHint["reviewDecision"],
+  };
+}
+
+export function useCheckoutPrStatusQuery({
+  serverId,
+  cwd,
+  enabled = true,
+}: UseCheckoutPrStatusQueryOptions) {
+  const queryClient = useQueryClient();
+  const client = useHostRuntimeClient(serverId);
+  const isConnected = useHostRuntimeIsConnected(serverId);
+
+  useEffect(() => {
+    if (!client || !isConnected || !cwd) {
+      return;
+    }
+
+    return client.on("checkout_status_update", (message) => {
+      const prStatus = message.payload.prStatus;
+      if (!prStatus || prStatus.cwd !== cwd) {
+        return;
+      }
+      queryClient.setQueryData(checkoutPrStatusQueryKey(serverId, cwd), prStatus);
+    });
+  }, [client, isConnected, cwd, queryClient, serverId]);
+
+  const query = useQuery({
+    queryKey: checkoutPrStatusQueryKey(serverId, cwd),
+    queryFn: async () => {
+      if (!client) {
+        throw new Error("Daemon client not available");
+      }
+      return await client.checkoutPrStatus(cwd);
+    },
+    enabled: !!client && isConnected && !!cwd && enabled,
+    staleTime: Infinity,
+    refetchOnMount: false,
+    refetchOnReconnect: false,
+    refetchOnWindowFocus: false,
+  });
+
+  return {
+    status: query.data?.status ?? null,
+    githubFeaturesEnabled: query.data?.githubFeaturesEnabled ?? true,
+    payloadError: query.data?.error ?? null,
+    isLoading: query.isLoading,
+    isFetching: query.isFetching,
+    isError: query.isError,
+    error: query.error,
+  };
+}
+
+export function useWorkspacePrHint({
+  serverId,
+  cwd,
+  enabled = true,
+}: UseCheckoutPrStatusQueryOptions): PrHint | null {
+  const queryClient = useQueryClient();
+  const client = useHostRuntimeClient(serverId);
+  const isConnected = useHostRuntimeIsConnected(serverId);
+
+  useEffect(() => {
+    if (!client || !isConnected || !cwd) {
+      return;
+    }
+
+    return client.on("checkout_status_update", (message) => {
+      const prStatus = message.payload.prStatus;
+      if (!prStatus || prStatus.cwd !== cwd) {
+        return;
+      }
+      queryClient.setQueryData(checkoutPrStatusQueryKey(serverId, cwd), prStatus);
+    });
+  }, [client, isConnected, cwd, queryClient, serverId]);
+
+  const query = useQuery<CheckoutPrStatusPayload, Error, PrHint | null>({
+    queryKey: checkoutPrStatusQueryKey(serverId, cwd),
+    queryFn: async () => {
+      if (!client) {
+        throw new Error("Daemon client not available");
+      }
+      return await client.checkoutPrStatus(cwd);
+    },
+    enabled: !!client && isConnected && !!cwd && enabled,
+    staleTime: Infinity,
+    refetchOnMount: false,
+    refetchOnReconnect: false,
+    refetchOnWindowFocus: false,
+    select: selectWorkspacePrHint,
+  });
+
+  return query.data ?? null;
+}