[Android][A3] Font assets on Android (bundled .otf reaches FreeType through the .so packaging)

[clintecker]

The bundled math .otfs must load via FreeType from the AAR's packaged asset path. Loading from bytes already works on Linux; the open question is SwiftPM resource bundling reaching the asset path inside the .so/AAR.

Acceptance

• FreeType loads each bundled font from the packaged path on-device.
• .so size measured; decide whether non-default fonts become an optional artifact.

Depends on: C0 (blocked on Android).

[clintecker]

Largely resolved by #94: the mechanism for bundled fonts to reach FreeType on Android is now proven — ship the .otfs as APK assets, extract to filesDir at first run, and hand the path to the native lib via vinculum_set_font_dir (Bundle.module traps in an APK, so it's bypassed). Demonstrated end-to-end in android/smoke/ — the emulator run loaded all 5 fonts and rendered. What's left here is folding that extraction into the real AAR/Gradle packaging (part of #84) rather than the smoke harness.