[260514-eanlcc] scaffold smell-scanner + default-off + extension filter

[DarkCodePE]

Implements 260514-eanlcc

Layers

CLI + Core + Test

Acceptance Criteria

AC-1: Default-off (SMELL_SCAN_ENABLE unset or =0 -> scanner exits 0 silently).

verify:
  - cmd: node .claude/helpers/smell-scanner.mjs --action scan --file foo.mjs --dry-run
    expect_stdout_match: scanner disabled
    expect_exit_code: 0

AC-2: Extension filter (non-code extensions skipped with log).

verify:
  - cmd: SMELL_SCAN_ENABLE=1 node .claude/helpers/smell-scanner.mjs --action scan --file README.md --dry-run
    expect_stdout_match: non-code extension, skipping
    expect_exit_code: 0

Dependencies

None (first slice).

Definition of Done

AC-1 and AC-2 pass. Module scaffold with parseFlags, action dispatcher, fail() helper. CLI flags: --action, --file, --dry-run. RED tests added first.

Plan

docs/plans/260514-eanlcc-smell-scanner.md (Slice 1)

[DarkCodePE]

[ac-verifier] closed: AC-1 pass, AC-2 pass, AC-3 pass, AC-4 pass, AC-5 pass, AC-6 pass, AC-7 pass, AC-8 pass, AC-9 pass. U-ID: 260514-eanlcc