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/server/src/shared/messages.checkout-pr-schema.test.ts

@@ -0,0 +1,47 @@
+import { describe, expect, test } from "vitest";
+
+import { CheckoutPrMergeRequestSchema, CheckoutPrStatusSchema } from "./messages.js";
+
+describe("checkout PR schemas", () => {
+  test("parses PR status payloads without mergeability", () => {
+    expect(
+      CheckoutPrStatusSchema.parse({
+        number: 42,
+        url: "https://github.com/getpaseo/paseo/pull/42",
+        title: "Ship it",
+        state: "open",
+        baseRefName: "main",
+        headRefName: "feature/ship-it",
+        isMerged: false,
+      }),
+    ).toMatchObject({
+      number: 42,
+      mergeable: "UNKNOWN",
+    });
+  });
+
+  test.each(["merge", "squash", "rebase"] as const)(
+    "accepts %s as a PR merge method",
+    (mergeMethod) => {
+      expect(
+        CheckoutPrMergeRequestSchema.parse({
+          type: "checkout_pr_merge_request",
+          cwd: "/tmp/repo",
+          mergeMethod,
+          requestId: "request-merge-pr",
+        }),
+      ).toMatchObject({ mergeMethod });
+    },
+  );
+
+  test("rejects unknown PR merge methods", () => {
+    expect(() =>
+      CheckoutPrMergeRequestSchema.parse({
+        type: "checkout_pr_merge_request",
+        cwd: "/tmp/repo",
+        mergeMethod: "auto",
+        requestId: "request-merge-pr",
+      }),
+    ).toThrow();
+  });
+});

packages/server/src/shared/messages.ts

@@ -1272,6 +1272,13 @@ export const CheckoutPrCreateRequestSchema = z.object({
   requestId: z.string(),
 });
 
+export const CheckoutPrMergeRequestSchema = z.object({
+  type: z.literal("checkout_pr_merge_request"),
+  cwd: z.string(),
+  mergeMethod: z.enum(["merge", "squash", "rebase"]),
+  requestId: z.string(),
+});
+
 export const CheckoutPrStatusRequestSchema = z.object({
   type: z.literal("checkout_pr_status_request"),
   cwd: z.string(),
@@ -1719,6 +1726,7 @@ export const SessionInboundMessageSchema = z.discriminatedUnion("type", [
   CheckoutPullRequestSchema,
   CheckoutPushRequestSchema,
   CheckoutPrCreateRequestSchema,
+  CheckoutPrMergeRequestSchema,
   CheckoutPrStatusRequestSchema,
   PullRequestTimelineRequestSchema,
   CheckoutSwitchBranchRequestSchema,
@@ -2661,6 +2669,11 @@ export const CheckoutPrStatusSchema = z.object({
   headRefName: z.string(),
   isMerged: z.boolean(),
   isDraft: z.boolean().optional().default(false),
+  mergeable: z
+    .enum(["MERGEABLE", "CONFLICTING", "UNKNOWN"])
+    .catch("UNKNOWN")
+    .optional()
+    .default("UNKNOWN"),
   checks: z
     .array(
       z.object({
@@ -2782,6 +2795,16 @@ export const CheckoutPrCreateResponseSchema = z.object({
   }),
 });
 
+export const CheckoutPrMergeResponseSchema = z.object({
+  type: z.literal("checkout_pr_merge_response"),
+  payload: z.object({
+    cwd: z.string(),
+    success: z.boolean(),
+    error: CheckoutErrorSchema.nullable(),
+    requestId: z.string(),
+  }),
+});
+
 export const CheckoutPrStatusResponseSchema = z.object({
   type: z.literal("checkout_pr_status_response"),
   payload: CheckoutPrStatusPayloadSchema,
@@ -3338,6 +3361,7 @@ export const SessionOutboundMessageSchema = z.discriminatedUnion("type", [
   CheckoutPullResponseSchema,
   CheckoutPushResponseSchema,
   CheckoutPrCreateResponseSchema,
+  CheckoutPrMergeResponseSchema,
   CheckoutPrStatusResponseSchema,
   PullRequestTimelineResponseSchema,
   CheckoutSwitchBranchResponseSchema,
@@ -3585,6 +3609,10 @@ export type CheckoutPushRequest = z.infer<typeof CheckoutPushRequestSchema>;
 export type CheckoutPushResponse = z.infer<typeof CheckoutPushResponseSchema>;
 export type CheckoutPrCreateRequest = z.infer<typeof CheckoutPrCreateRequestSchema>;
 export type CheckoutPrCreateResponse = z.infer<typeof CheckoutPrCreateResponseSchema>;
+export type CheckoutPrMergeRequest = z.infer<typeof CheckoutPrMergeRequestSchema>;
+export type CheckoutPrMergeResponse = z.infer<typeof CheckoutPrMergeResponseSchema>;
+export type CheckoutPrMergeMethod = z.infer<typeof CheckoutPrMergeRequestSchema>["mergeMethod"];
+export type PullRequestMergeable = z.infer<typeof CheckoutPrStatusSchema>["mergeable"];
 export type CheckoutPrStatusRequest = z.infer<typeof CheckoutPrStatusRequestSchema>;
 export type CheckoutPrStatusResponse = z.infer<typeof CheckoutPrStatusResponseSchema>;
 export type PullRequestTimelineRequest = z.infer<typeof PullRequestTimelineRequestSchema>;