feat(cli): Add deterministic detect command for rule routing

[thecodedrift]

Add taskless detect --json: an offline, deterministic scan of the working directory that emits the signals the routing recipes consume.

It reports configured linters (evidenced by config files, pyproject.toml [tool.x] tables, or package.json dependencies), inferred languages and frameworks, and the styles of the repo's own existing rules. There is no LLM, no network, and no auth — the command is a stable, testable input that keeps the routing agent from hallucinating the repo's tooling.

By design, detect reports only repo signals; it never matches a request against a catalog of packaged rules. That judgment is effectively infinite across ecosystems and is left to the existing recipe (repo + WebFetch), not baked into the CLI.

Implementation is a focused scanner module (detect/scan.ts) behind a thin command, a Zod output schema, and integration tests covering linter detection across eslint/ruff/rubocop/biome/stylelint, language/framework inference, the no-packaged-rule-claims contract, and the offline/no-auth guarantee.

Stacked on #23 (the change contract). Review/merge that first.

Refs TSKL Runtime Rules

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• main
  • docs(openspec): Propose local-rule-routing change #23
    • feat(cli): Add deterministic detect command for rule routing 👈
      • feat(cli): Add route/existing/static/remote authoring recipes #25
        • feat(cli): Surface routing recipes in the help index #26
          • feat(skill): Engage routing when a linter is named #27
            • test(cli): Add route honesty eval fixtures and finalize change #28

^{Stack generated by Git Town}

[Copilot]

Pull request overview

Adds a new taskless detect subcommand intended to provide a deterministic, offline JSON “repo signals” scan that downstream rule-routing recipes can consume (linters, languages/frameworks, and existing local rule styles).

Changes:

• Introduces a filesystem-only repository scanner (packages/cli/src/detect/scan.ts) to infer linters, languages/frameworks, and local rule style signals.
• Adds a detect CLI command with --json output and registers it in the CLI entrypoint.
• Adds Vitest integration tests for linter detection, language/framework inference, rule-style surfacing, and stable JSON shape.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
packages/cli/test/detect.test.ts	New integration tests that execute the built CLI and validate detect JSON signals.
packages/cli/src/schemas/detect.ts	New Zod schema describing taskless detect --json output.
packages/cli/src/index.ts	Registers the new detect subcommand.
packages/cli/src/detect/scan.ts	Implements deterministic repo signal scanning for linters/languages/frameworks/rule styles.
packages/cli/src/commands/detect.ts	Adds the detect CLI command and JSON/human output modes.
openspec/changes/local-rule-routing/tasks.md	Adds/updates spec task tracking for the local-rule-routing change set.

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[thecodedrift]

Comments included around how we think about this parse. At a high level, I think we can use a tool like ast-grep or glob to quickly scan for files that tell us "what" we see, and then a second parallel detailed scan can answer the next level question around what linters are in use. I just generally think this procedural design is better expressed through config which we did at the top and then gave up on halfway through.

The benefits of this mean that as we add more linters and languages, it's just config changes, not adding code to the detect file.