Add 'land.style' option. - #102

…stead of patches (#74)

## Summary

Phase 6 of the autoland step-abstraction stack. `Services` becomes the real seam: everything a plan's execution does goes through the `Services` it is given, and the autoland tests inject fakes there instead of patching module attributes.

**What now takes `Services`**
- `waits.py`: `wait_for_approval`, `wait_for_checks`, `wait_for_mergeable`, `enqueue_and_wait`, `wait_for_workflow`, and their helpers (`_poll_read`, `_refresh_review`, `_rewait_after_retry`) take a keyword `services` and use its `github`, `ui`, and `sleep` instead of `gh.github`, `runtime.console`, and `runtime.resilient_sleep`. `_Ancestry(common, services)` asks `services.repo` for local ancestry and the fetch, and `services.github` for the compare API.
- `native_stack.py`: `land_as_native_stack(..., services=)`, `_native_stack_for`, and `_await_native_stack_merge` use `services.github`, `services.ui`, and `services.sleep`. The waits before a stack merge go through `services.waits`, and the landed-SHA lookup and rebase through `services.repo`. `StackMergeUnit` passes `uc.services`.
- New `autoland/repo.py`: `GitRepo(github, ui)`, the production `Repo`. It holds what used to be `waits.rebase_and_resubmit`, `waits._refresh_last_landed_sha` (now `landed_sha`, which returns the SHA instead of writing it into a context), and `waits._local_is_ancestor` (now `is_ancestor`), plus `fetch_target`. The commands they run are unchanged. `Repo` gains `fetch_target` and `is_ancestor`.
- `engine.print_execution_preview` takes the `ui` to print to.
- `commands._run_fresh`, `_run_resume`, and `_replan` take an optional keyword `services` (default `Services.production()`), which they use for the preview and pass to `_land`. This is the composition root, and tests inject there instead of patching `Services.production`.

**The `Services` shape**: a frozen dataclass of `github: gh.GitHub`, `ui: UI`, `sleep: Callable[[int], float]`, `repo: Repo`, and `waits: Waits`. `waits` defaults to `PollingWaits(self)`, the real wait loops polling through the same services. It always rebinds to the `Services` it belongs to, so `dataclasses.replace(services, github=...)` gives waits that poll the new client. `Waits` stays a service (now with `wait_for_mergeable`, which the stack merge needs) because it is still the right seam for step-level and stack-merge tests: they check what a step or a unit does when a wait succeeds or fails, without scripting a GitHub to get there.

**`Services.production()` binds the real objects directly**: `gh.github`, `ConsoleUI(runtime.console)`, `runtime.resilient_sleep`, and `GitRepo(gh.github, ui)`, as they are when it's called. The call-time delegates (`_LiveGitHub`, `_ModuleWaits`, `_GitRepo`, `_resilient_sleep`) are gone.

**Module singletons that remain, and why**
- `runtime.console`: the command flows' own output and prompts (`commands`), `--status` (`status`, `display.print_status`), plan file/editor messages (`plan`), worktree messages, and the shell runner, which echoes each command (`$ gh ...`) from inside `runtime.run`. The real `gh.GitHub` client runs through `runtime.run`, so its echo stays there as well. `resilient_sleep` also prints its wake-up notice there.
- `gh.github`: plan parsing (`plan.parse_plan`'s merged-PR check, PR-URL resolution in `steps/land.py`) and stack discovery (`discovery.enrich_stack`). All of these run before a plan executes.
- `runtime.resilient_sleep`, `runtime.HAVE_RICH`, `display.GLYPHS`: production defaults and display settings. The golden harness patches these, and `Services.production()` picks up the patched sleep and console when the run starts.

**Test fakes** (new `tests/autoland_fakes.py`), consolidating the fakes that were spread over four files:
- `FakeUI` (scripted answers, recorded output), and `FakeWaits` (outcome functions per wait; records `calls` and `entries`, `waited(kind)`, the workflow steps and target SHAs).
- `FakeRepo`: landed SHAs from a table, counted rebases (optionally failing) and fetches, plus known ancestry and what a fetch adds to it.
- `FakeGitHub`: an in-memory GitHub (PR states, reviews, checks, merge commits, the merge queue, workflow runs, compare results, GitHub stacks), merging `_FakeNativeStackGitHub` from `test_autoland.py`. It logs every call (`calls`, `called(method)`), and `script(method, *replies)` answers the next calls with values, exceptions, or callables before it goes back to its state.
- `ForbiddenGitHub` / `forbidden_sleep`, for tests where a step must not use them directly.
- `FakeSleep(limit=None)`: records sleeps, and after `limit` of them raises `StopPolling` to end a wait that is still waiting.
- `FakeServices`: a dataclass of the fakes, with `.services`. `FakeServices()` uses `FakeWaits`, and `FakeServices.polling(...)` runs the real wait loops over the fakes. `github` can also be a real `gh.GitHub()` for tests that fake `gh` at the subprocess boundary.
- `OPTS` and `stack()` move there too.

**Patch counts** (lines with `mocker.patch` / `mock.patch` / `monkeypatch.setattr`, before → after):
- `tests/test_autoland.py`: 102 → 34. What remains: the subprocess boundary (`shell_commands.run_with_retry` via one `_shell` helper, `subprocess.run`, `RETRY_DELAY`, `stack_pr.git.run_shell_command`), stack-pr cli functions (`deduce_base`, `command_submit`, `get_stack`, `get_current_branch_name`), plan parsing and discovery outside the injected path (`gh.github.owner_repo` / `pr_state`, `discovery.*`), the command-flow seams (`commands.Worktree` / `AutolandLock` / `_unpushed_changes`, `engine.execute_plan`), and console/display singletons (`runtime.console`, `HAVE_RICH`, `display.GLYPHS`, `sys.stdout`).
- `tests/test_autoland_interrupt.py`: 9 → 7. `Services.production` is no longer patched, in the tests or in the subprocess script. The git/cli stubs, `enrich_stack`, and `Worktree` remain.
- `tests/test_autoland_optimize.py`: 4 → 0. `StackMergeUnit` tests now run the real `land_as_native_stack` against `FakeServices`. The preview tests print to a `FakeUI`.
- `tests/test_autoland_step_execution.py`: 0 → 0. Its fakes moved to `autoland_fakes.py`.
- `tests/autoland_scenarios.py` (golden harness): 12 → 12, unchanged. It still fakes at `run_shell_command` / `get_command_output`, so the real client runs.

**How the migrated tests changed**, each checking the same behavior:
- Wait-loop tests run the real loops through `FakeServices.polling()`: workflow ancestry (local, after a fetch, then the compare API; verdict caching), approval by review decision, and failed/incomplete runs. They no longer patch `gh.github.*`, `runtime.run`, or `runtime.resilient_sleep`.
- The failed-read tests still use the real `gh.GitHub()` with `gh` faked at the subprocess boundary. They no longer patch the sleep. The two merge-queue ones script the mergeable read and the enqueue instead of patching `waits.wait_for_mergeable` and `gh.github.enqueue`.
- The native-stack engine tests run `engine.execute_plan` with `FakeGitHub` and `FakeWaits` (their one-at-a-time landing recorded as `queue` waits, and the rebases counted on `FakeRepo`), instead of 11 patches.
- `GitHub.poll_merge` tests use a small subclass of the real client with a canned PR state, instead of patching the singleton's methods.
- `StackMergeUnit` tests: "merged PRs" is now the stack-creation requests `FakeGitHub` received. A fall-through is a stack that can't be created. The stack-merge abort is a real rebase failure ("Rebase failed after merging modular#102: boom", so the test stack has a third PR above the run). "Not stack-merged" is checked as no GitHub calls and no output, instead of `assert_not_called` on a patched function.

No user-visible change. Console output, checkpoints, and status output are byte-for-byte identical.

## Test plan

- [x] The golden autoland scenarios pass with no golden files regenerated.
- [x] Every migrated test checks the same behavior through injected fakes, and each autoland test file passes on its own.
- [x] New: `dataclasses.replace` of a `Services`'s `github` gives waits that poll the new client and never the old one.
- [x] The full suite passes with an empty `GH_CONFIG_DIR` and `GH_TOKEN` unset.
- [ ] Manual: run a real `stack-pr autoland` (with and without `--merge-as-stack`) on a small stack and check that the output and the `--status` report are unchanged.

🤖 Generated with [Claude Code](https://claude.com/claude-code)


stack-info: PR: #74, branch: micahjsmith/stack/8

Co-authored-by: Claude Opus 5.5 (1M context) <[email protected]>