feat(cicontext): rules:changes: path-glob evaluation; 100% test coverage

- Add --changes PATH and --changes-from REF flags to glint check and glint graph
  for rules:changes: evaluation. --changes marks files explicitly; --changes-from
  runs git diff --name-only <REF> automatically. Both flags can be combined.
- Implement doublestar glob matching (*, ** across path segments) in EvalJob and
  EvalWorkflow; extended {paths, compare_to} map form supported.
- Without --changes/--changes-from the condition stays permissive (existing behaviour).
- Context summary line now shows changed-file count when file data is provided.
- Achieve 100% statement coverage: comprehensive tests added across all packages;
  removed provably dead code; added testability seams (exit, userHomeDirFn,
  execCommandOutput variables) to cover previously unreachable paths.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ROADMAP.md

@@ -22,9 +22,9 @@ Pass `--branch`, `--tag`, `--source`, or `--var` to `glint check` or `glint grap
 - ~~**YAML `\/` escape in double-quoted strings**~~ — ✓ shipped v0.2.13; regex patterns like `/^us\//` in double-quoted `if:` blocks no longer cause a parse error
 - ~~**Workflow rule strict evaluation**~~ — ✓ shipped v0.2.14; unparseable `if:` skips the rule instead of matching everything; prevents wrong variables being injected
 - ~~**Single `=` operator**~~ — ✓ shipped v0.2.14; bare `=` accepted as alias for `==` in `rules:if:` expressions
+- ~~**`rules:changes:` evaluation**~~ — ✓ shipped v0.2.21; `--changes PATH` and `--changes-from REF` flags; doublestar glob matching (`*` within segment, `**` across segments); permissive when no file list provided
 - **Multi-context simulation** — run multiple contexts in one invocation and print a comparison table (`--context branch=main --context branch=develop --context tag=v1.0.0`)
 - **Context-scoped linting** — skip `needs:`/`dependencies:` cross-checks for jobs that are statically unreachable in the given context
-- **`rules:changes:` evaluation** — path glob evaluation against the local git tree
 
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