Lemenzo Gallery v1.12 — production hardening

- Fixed SmartCategoryClassifier Java compile blocker from v1.11.
- Added real host-test execution with javac and four pure-Java regression suites.
- Static validator now performs comment/literal-aware Java delimiter checks.
- Added Local Auto Enhance: histogram/dynamic-range/color-cast analysis, entirely on-device and non-destructive.
- Added local visual document detection from small MediaStore thumbnails.
- Added local Selfies smart category using Android FaceDetector on transient thumbnails; no biometric templates are stored.
- No INTERNET or MANAGE_EXTERNAL_STORAGE permission.
- Motion Photos remain verified from XMP + MP4 tail, never filename heuristics.

Production verification still requires the Android 16 Soong build, atest, and Pixel runtime/stress tests.