fix: Android 코덱 호환성 + 스톡영상 스크린녹화 필터링 + Gitea URL 업데이트

- video_assembler: yuv420p, profile high, level 4.0, movflags faststart 추가
- stock_fetcher: AI/UI 키워드 실사영상으로 변환, 스크린녹화 태그 차단
- CLAUDE.md: Gitea URL https://gitea.gru.farm/ 으로 변경

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bots/shorts/video_assembler.py

@@ -128,6 +128,7 @@ def _concat_with_xfade(clips: list[Path], output: Path, crossfade: float, ffmpeg
         '-filter_complex', filter_complex,
         '-map', prev_label,
         '-c:v', 'libx264', '-crf', '23', '-preset', 'fast',
+        '-pix_fmt', 'yuv420p',
         '-an', '-r', '30',
         str(output),
     ]
@@ -151,6 +152,7 @@ def _concat_simple(clips: list[Path], output: Path, ffmpeg: str) -> bool:
         '-f', 'concat', '-safe', '0',
         '-i', str(list_file),
         '-c:v', 'libx264', '-crf', '23', '-preset', 'fast',
+        '-pix_fmt', 'yuv420p',
         '-an', '-r', '30',
         str(output),
     ]
@@ -240,8 +242,11 @@ def _assemble_final(
             f'apad=pad_dur=0.2'  # 루프 최적화: 0.2s 무음
         ),
         '-c:v', codec, '-crf', str(crf), '-preset', 'medium',
+        '-pix_fmt', 'yuv420p',
+        '-profile:v', 'high', '-level', '4.0',
         '-c:a', audio_codec, '-b:a', audio_bitrate,
         '-r', str(vid_cfg.get('fps', 30)),
+        '-movflags', '+faststart',
         '-shortest',
         str(output),
     ]
@@ -266,7 +271,9 @@ def _rerender_smaller(src: Path, dst: Path, ffmpeg: str) -> bool:
     cmd = [
         ffmpeg, '-y', '-i', str(src),
         '-c:v', 'libx264', '-crf', '23', '-preset', 'medium',
+        '-pix_fmt', 'yuv420p', '-profile:v', 'high', '-level', '4.0',
         '-c:a', 'aac', '-b:a', '128k',
+        '-movflags', '+faststart',
         str(dst),
     ]
     try: