fix(windsurf): include YAML frontmatter when generating rule files

[dyoshikawa]

Motivation

• Windsurf requires YAML frontmatter (title, trigger, globs) in .windsurf/rules/*.md files, but generated files previously contained only the rule body.
• Ensure generated Windsurf rule files include the required frontmatter so they work correctly in the Windsurf toolchain.

Description

• Serialize Windsurf frontmatter by importing stringifyFrontmatter and adding a WindsurfRuleFrontmatter shape.
• Implement buildWindsurfFrontmatter() to derive title from rulesync description (fallback to filename), set trigger to glob when specific globs exist otherwise always_on, and include globs only for glob triggers.
• Update WindsurfRule.fromRulesyncRule() to build tool params, compose Windsurf frontmatter, and set fileContent to stringifyFrontmatter(body, windsurfFrontmatter).
• Update src/features/rules/windsurf-rule.test.ts to assert the new frontmatter output and add coverage for glob-triggered rules.

Testing

• Ran the Windsurf unit tests with pnpm vitest run src/features/rules/windsurf-rule.test.ts and they passed (38 passed).
• Ran full project checks with pnpm cicheck, which completed formatting, linting, typechecks and the full test suite successfully (all automated checks passed; full test run completed without failures).

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Codex Task

[Copilot]

Pull request overview

Adds Windsurf-required YAML frontmatter to generated .windsurf/rules/*.md files so Windsurf can correctly interpret rule metadata during its rule loading pipeline.

Changes:

• Generate Windsurf rule file content via stringifyFrontmatter(), emitting title, trigger, and optional globs.
• Introduce buildWindsurfFrontmatter() to derive Windsurf frontmatter from Rulesync rule metadata.
• Update unit tests to assert the new frontmatter output, including a glob-triggered example.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/features/rules/windsurf-rule.ts	Builds and serializes Windsurf YAML frontmatter into generated rule file content.
src/features/rules/windsurf-rule.test.ts	Updates assertions to match the new frontmatter-bearing output and adds a glob-trigger test.

[Copilot]

hasSpecificGlobs treats any occurrence of "/*" as meaning "no specific globs". That misclassifies cases like ["**/*", "src/**/*.ts"] (should still be trigger: glob) and also treats "*" as specific even though it’s a wildcard used elsewhere in the codebase. Consider computing specificity as “at least one glob that isn’t "/" or ""” (and treat mixed wildcard+specific as specific).

[Copilot]

fromRulesyncRule() now writes Windsurf YAML frontmatter into fileContent, but WindsurfRule.fromFile() doesn’t parse/strip that frontmatter. As a result, reading a generated .windsurf/rules/*.md file will keep the frontmatter in the body and toRulesyncRuleDefault() will round-trip it into the Rulesync rule body (and you also lose the ability to map title/trigger/globs back into Rulesync metadata). Consider updating fromFile() to parseFrontmatter() and populate description/globs from the parsed Windsurf frontmatter, storing only the markdown body as fileContent.