Add interactive explorer and duplicate audit

[MicroMilo]

What changed

• Add a focused, metadata-first terminal explorer for local paths.
• Add bounded local file previews, responsive Codex questions, persistent answers, Vim navigation, and folder expansion.
• Add opt-in exact duplicate detection with local hashing, redacted reports, overlap warnings, and approval gates.
• Add bilingual documentation, examples, tests, and synthetic demo assets.

Why

The previous skill could produce a report, but it was difficult to inspect a specific area interactively. This version lets a person map a path, inspect one node, ask a local AI about its likely purpose, and review duplicate evidence without changing files.

Safety

The default flow is read-only and metadata-first. File previews are bounded and stay local; duplicate hashing is opt-in; reports do not expose raw hashes. The demo assets are synthetic and contain no personal paths.

Validation

• python3 -m py_compile audit-local-files/scripts/*.py tests/*.py
• python3 tests/smoke_test.py
• python3 tests/contract_test.py
• python3 tests/duplicate_test.py
• python3 tests/interactive_test.py
• python3 tests/tui_test.py
• git diff --check

The demo video is intentionally a review artifact for this version; its narration and visual explanation can be refined in a follow-up.