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/ios/CodecCapability.swift

@@ -0,0 +1,21 @@
+import VideoToolbox
+
+enum CodecCapability {
+  static let isHardwareHEVCEncodeAvailable: Bool = {
+    var encoderListCF: CFArray?
+    let status = VTCopyVideoEncoderList(nil, &encoderListCF)
+    guard status == noErr, let encoderList = encoderListCF as? [[String: Any]] else {
+      return false
+    }
+    return encoderList.contains { encoder in
+      guard let codecTypeValue = encoder[kVTVideoEncoderList_CodecType as String] as? Int,
+            codecTypeValue == Int(kCMVideoCodecType_HEVC) else {
+        return false
+      }
+      if let isHardware = encoder[kVTVideoEncoderList_IsHardwareAccelerated as String] as? Bool {
+        return isHardware
+      }
+      return true
+    }
+  }()
+}