feat(pre-commit): replace TOML filter with Rust summary handler + uv run alias

[jugrajsingh]

Summary

Replaces the TOML-based pre-commit filter with a Rust subcommand that produces a real one-line summary plus verbatim blocks for failing hooks. Also recognises uv run pre-commit as an alias so the rewrite layer fires inside uv-managed projects.

Closes / supersedes the implementation merged via #184 (which the TOML pipeline couldn't deliver on — counting and conditional summarisation aren't expressible as line-strip regexes).

Motivation

The previous src/filters/pre-commit.toml only stripped [INFO] Installing environment install noise plus blank lines, then capped at 40 lines. On real passing runs (9 hooks of Passed/Skipped lines) it left output essentially unchanged — measured savings ~0% on representative workloads.

The TOML pipeline (strip_lines_matching, max_lines, replace, …) can drop and truncate lines, but it can't:

• count hook outcomes
• emit a single summary like 9 hooks: 7 passed, 2 skipped
• conditionally keep failure context verbatim while collapsing pass output
• detect a uv venv and route via uv run pre-commit

What's in this PR

1. Rust handler (src/cmds/python/precommit_cmd.rs)

Parses each line, buckets hooks by status, and renders:

• Pass-only: 9 hooks: 7 passed, 2 skipped
• With failures: summary line + verbatim block per failed hook (keeps hook id, exit code, file:line errors)
• With autofixes: 9 hooks: 8 passed, 1 autofixed — re-stage and retry

Pass-through for install, autoupdate, clean, --help, --version, etc. — only run is filtered.

2. uv run pre-commit alias

Extends the existing pre-commit rule:

• pattern: r"^(?:uv run )?pre-commit\b"
• rewrite_prefixes: &["uv run pre-commit", "pre-commit"] (longest first)

Handler does auto-resolution: prefers pre-commit on PATH; falls back to uv run pre-commit when uv is on PATH and a pyproject.toml is reachable in cwd or an ancestor. Falls through to plain pre-commit otherwise so command-not-found surfaces cleanly.

3. Commands::PreCommit clap variant

Adds the missing top-level variant (clap name = "pre-commit") and dispatches to precommit_cmd::run. Registered in is_operational_command.

4. Removes the now-redundant src/filters/pre-commit.toml

The Rust handler supersedes it. Tests for test_builtin_filter_count etc. updated accordingly (59 → 58).

Measured impact

• Real-world run in a 9-hook config: 720 bytes → 29 bytes (96.0% reduction)
• Unit test asserts ≥60% savings on the captured pass fixture (passes at ~80%)
• Failure case keeps full verbatim error block — no information loss

Tests

• 11 unit tests in precommit_cmd.rs (regex parsing, summary rendering, autofix detection, pyproject walk, savings assertion against real fixture)
• 3 rewrite-rule tests in discover/registry.rs (bare form, uv run form, no-args form)
• All 1915 existing tests still pass
• cargo fmt --all, cargo clippy --all-targets, cargo test --all all clean

Notes for reviewers

• Real fixtures in tests/fixtures/pre_commit_{pass,fail}.txt were captured from actual pre-commit runs and sanitised (no internal paths).
• No new dependencies added.
• No new unsafe, no async, no unwrap() outside lazy_static! regex literal.
• The handler honours rtk's fallback rule: if the filter function panics or errors, the runner falls back to raw output.

Refs

• Feature request: pre-commit / linter output filter support #184 — original feature request (closed with the TOML approach, which we found insufficient in practice)
• Add wrappers for common dev/infra commands (kubectl exec, uv run, sqlc, flutter, git checkout/remote, gh auth, npm install/test, npx jest --watch, env-prefixed go run) #1711 — wishlist mentioning uv run wrappers (this addresses the pre-commit case)

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