Add expo-bluesky-video-compress native module

Replaces react-native-compressor's video path with a local Expo module.

Native pipeline:
- iOS: AVAssetReader + AVMutableVideoComposition + AVAssetWriter with
  VideoToolbox encode, BGRA reader for HDR -> SDR conversion, BT.709
  color tagging, DataRateLimits hard cap, AAC re-encode.
- Android: MediaExtractor -> MediaCodec(decoder) -> GL pipeline ->
  MediaCodec(encoder) -> MediaMuxer. BITRATE_MODE_CBR for tight target
  enforcement, GL transform-matrix rotation (no double-rotation),
  raw AAC passthrough, hardware encoder selection with software
  fallback, QTI AVC denylist.

Codec selection: 'auto' resolves to h264 (HLS pipeline + licensing).
HEVC remains opt-in via codec: 'hevc' for future feature-flagged use.

compress.ts adds probe-based smart-skip: clips that are already at or
below 5 Mbps / 1920px / 100MB bypass re-encoding entirely.

react-native-compressor stays as a dep for now since pickVideo and
VideoTranscodeBackdrop still use its non-compression helpers; full
removal is a follow-up.

modules/expo-bluesky-video-compress/expo-module.config.json

@@ -0,0 +1,9 @@
+{
+  "platforms": ["ios", "android"],
+  "ios": {
+    "modules": ["ExpoBlueskyVideoCompressModule"]
+  },
+  "android": {
+    "modules": ["expo.modules.blueskyvideocompress.ExpoBlueskyVideoCompressModule"]
+  }
+}