feat(rust): port ci scopes-send to native Rust (Phase 1.4)

First ``ci`` command to go native. Straight HTTP POST to Mergify
carrying the scopes detected for a pull request, no new
infrastructure needed beyond what the config pilot already
established.

## What ports natively

``mergify ci scopes-send [-r REPO] [-p NUMBER] [-t TOKEN] [-u URL]
[-s SCOPE...] [--scopes-json FILE] [--scopes-file FILE]``:

1. Resolves the repository: ``--repository`` flag → ``GITHUB_REPOSITORY``
   env → error.
2. Resolves the pull-request number: ``--pull-request`` flag →
   ``GITHUB_EVENT_PATH`` JSON (``.pull_request.number``) → ``None``.
   When ``None`` the command prints a skip message to stderr and
   returns 0 — matches Python's "no PR, nothing to send".
3. Resolves the token: ``--token`` flag → ``MERGIFY_TOKEN`` →
   ``GITHUB_TOKEN`` → error.
4. Resolves the API URL: ``--api-url`` flag → ``MERGIFY_API_URL`` →
   ``https://api.mergify.com``.
5. Collects scopes from up to three sources (combined in order):
   ``--scope`` repeated flags, ``--scopes-json`` (Pydantic
   ``DetectedScope`` dump), ``--scopes-file`` (plain text).
6. POSTs ``{"scopes": [...]}`` to
   ``/v1/repos/<repo>/pulls/<number>/scopes`` via the HTTP client.

``--file`` is a hidden deprecated alias for ``--scopes-json``.
When used, the command prints a deprecation warning to stderr
and proceeds — matches Python's ``click.echo(..., err=True)``.

## Layout

New ``mergify-ci`` crate under ``crates/``. The ``scopes_send``
module is self-contained (duplicates ``resolve_token`` /
``resolve_api_url`` from ``mergify-config::simulate`` for now —
they factor into ``mergify-core`` in a follow-up refactor PR
once another command needs them).

The binary's dispatch gains a ``Ci`` subcommand group, with
``scopes-send`` as its only native variant today. Everything else
under ``ci`` (``git-refs``, ``scopes``, ``scopes-send`` siblings)
still falls through to the Python shim. The native-intent
heuristic in ``detect_native`` now recognizes both the ``config``
and ``ci`` prefixes.

## Tests

11 new unit tests in ``mergify-ci::scopes_send``:

- Repository resolution: flag, env fallback, error
- Pull-request resolution: explicit, from event JSON, missing
- JSON file parsing (DetectedScope shape)
- Text file parsing (trims + strips blanks)
- End-to-end wiremock: combined scopes from all three sources
- End-to-end wiremock: deprecated ``--file`` emits warning
- End-to-end wiremock: skip-on-no-PR early-out

``PORT_STATUS.toml`` flips ``ci scopes-send`` from ``shimmed`` to
``native``. The port-guard test stays green.

Binary size: 8.3 MB → 8.4 MB. 51 Rust tests total.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Change-Id: I7ff9df90791786c3c26f8159249d91093ba34ec1

Author: jd

Cargo.lock

@@ -47,10 +47,6 @@ status = "shimmed"
 path = ["ci", "scopes"]
 status = "shimmed"
 
-[[command]]
-path = ["ci", "scopes-send"]
-status = "shimmed"
-
 [[command]]
 path = ["freeze", "create"]
 status = "shimmed"

PORT_STATUS.toml

@@ -0,0 +1,25 @@
+[package]
+name = "mergify-ci"
+version = "0.0.0"
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+repository.workspace = true
+authors.workspace = true
+description = "Native implementation of `mergify ci` subcommands."
+publish = false
+
+[dependencies]
+mergify-core = { path = "../mergify-core" }
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+url = "2"
+
+[dev-dependencies]
+tempfile = "3.14"
+temp-env = { version = "0.3", features = ["async_closure"] }
+tokio = { version = "1", default-features = false, features = ["macros", "rt", "time"] }
+wiremock = "0.6"
+
+[lints]
+workspace = true

crates/mergify-ci/Cargo.toml

@@ -0,0 +1,10 @@
+//! Native Rust implementation of the `mergify ci` subcommands.
+//!
+//! Phase 1.4 starts with `ci scopes-send` — straight HTTP POST to
+//! Mergify with the scopes detected for a pull request. Other ci
+//! commands (`git-refs`, `scopes`, `queue-info`, `junit-process`)
+//! land in follow-up PRs as the shared infrastructure they need
+//! (git-subprocess runner, GitHub event parser, `JUnit` XML reader)
+//! is built out.
+
+pub mod scopes_send;