test(cmd/mdsmith): add dedicated unit tests for runCheck/runFix

[jeduden]

Summary

Scheduled architecture audit (2026-08-02) of the 134 files touched
since the last sweep, following
docs/development/architecture/audit-checklist.md.

The one blocker: runCheck (cmd/mdsmith/check.go) and runFix
(cmd/mdsmith/fix.go) — the check and fix CLI subcommand entry
points — had no dedicated in-process unit test, only binary-spawn e2e
coverage. audit-checklist.md promotes a missing unit test to
blocker severity when the function is on a public surface such as a
CLI subcommand entry.

• Adds TestRunCheck_UnknownFlag_ExitsTwo,
  TestRunCheck_Stdin_ChecksSource,
  TestRunCheck_Files_ExitsOneOnDiagnostics,
  TestRunCheck_Discovered_ChecksConfiguredFiles,
  TestRunFix_UnknownFlag_ExitsTwo,
  TestRunFix_StdinArg_ExitsTwo,
  TestRunFix_Files_FixesGivenFile, and
  TestRunFix_Discovered_FixesConfiguredFiles to
  cmd/mdsmith/main_unit_test.go, matching the TestRunInit_*
  precedent set by the 2026-07-19 audit cycle.
• Records the full sweep in
  docs/development/architecture-audit.md (blockers/tax/nice-to-have,
  bumps audit-from).
• Files plans for the two structural tax findings:
  • plan/2608021915 —
    relocate list query subcommand logic out of main.go.
  • plan/2608021916 —
    split internal/githooks by responsibility (SRP).
• No blockers found elsewhere: no rule-to-rule imports, no
  reverse-layer imports, no Liskov breaks. The prior cycle's
  isClaimed dedup (plan 2607191918) is confirmed resolved.

Test plan

• go build ./...
• go test ./cmd/mdsmith/...
• go vet ./...
• go tool -modfile=tools/go.mod golangci-lint run (0 issues)
• mdsmith check . (clean, 569 files)

---

Generated by Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.71%. Comparing base (2ab4b29) to head (c9ecdd2).

Additional details and impacted files

Components	Coverage Δ
Go	98.70% <ø> (ø)
TypeScript	99.54% <ø> (ø)

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[Copilot]

Pull request overview

Adds in-process unit tests for the mdsmith check/mdsmith fix CLI entrypoints (runCheck / runFix) as part of the 2026-08-02 architecture audit sweep, and records the audit results plus follow-up plans.

Changes:

• Add dedicated unit tests in cmd/mdsmith/main_unit_test.go covering runCheck / runFix routing and key exit-code behaviors.
• Append the 2026-08-02 sweep results to the architecture audit log and bump the audit-from commit.
• Add two new architecture “tax” plan files and register them in PLAN.md.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
plan/2608021916_arch-fix-githooks-package-split.md	New plan capturing the SRP-driven split of internal/githooks into smaller responsibility-focused packages.
plan/2608021915_arch-fix-query-subcommand-placement.md	New plan capturing the refactor to move list query logic out of cmd/mdsmith/main.go.
PLAN.md	Registers the two newly added plan files in the plan catalog.
docs/development/architecture-audit.md	Records the 2026-08-02 audit findings, notes the new tests added, and updates the audit range.
cmd/mdsmith/main_unit_test.go	Adds the new unit tests for runCheck / runFix behaviors.

Suppressed comments (2)

cmd/mdsmith/main_unit_test.go:862

• runCheck resolves files via loadAndResolve(), which calls loadConfig() and will walk up the directory tree to discover .mdsmith.yml unless it hits a .git boundary. Add a .git marker under the temp dir to keep the test isolated from any parent config and to avoid the rootward discovery walk.

	dir := t.TempDir()
	t.Chdir(dir)
	require.NoError(t, os.WriteFile(filepath.Join(dir, "dirty.md"),
		[]byte("# Title\n\nHello   \n"), 0o644))

cmd/mdsmith/main_unit_test.go:920

• runFix → fixFiles uses loadAndResolve(), which will try to discover config by walking up directories until a .git boundary. Without a .git marker in the temp dir, this test can become environment-dependent (and does extra filesystem walking). Add the .git marker before calling runFix.

	dir := t.TempDir()
	t.Chdir(dir)
	path := filepath.Join(dir, "fixme.md")
	require.NoError(t, os.WriteFile(path, []byte("# Title\n\nHello   \n"), 0o644))