docs: add comprehensive documentation and test suite

- Add CLAUDE.md with project architecture and operation modes
- Add backend/README.md with setup and usage instructions
- Add test_backend.py with automated tests for config, database, and queue
- Update requirements.txt with optional dependencies structure
- Update .env.example with all configuration options

.env.example

@@ -1,6 +1,90 @@
+# ============================================
+# TranscriptorIO Configuration
+# ============================================
+
+# === Application Mode ===
+# Options: standalone, provider, or standalone,provider (hybrid mode)
+TRANSCRIPTARR_MODE=standalone
+
+# === Database Configuration ===
+# SQLite (default - no additional driver needed)
+DATABASE_URL=sqlite:///./transcriptarr.db
+
+# PostgreSQL example (requires psycopg2-binary)
+# DATABASE_URL=postgresql://user:password@localhost:5432/transcriptarr
+
+# MariaDB/MySQL example (requires pymysql)
+# DATABASE_URL=mariadb+pymysql://user:password@localhost:3306/transcriptarr
+
+# === Worker Configuration ===
+CONCURRENT_TRANSCRIPTIONS=2
+WHISPER_THREADS=4
+TRANSCRIBE_DEVICE=cpu
+CLEAR_VRAM_ON_COMPLETE=True
+
+# === Whisper Model Configuration ===
+# Options: tiny, base, small, medium, large-v3, large-v3-turbo, etc.
 WHISPER_MODEL=medium
-WEBHOOKPORT=9000
-TRANSCRIBE_DEVICE=gpu
+MODEL_PATH=./models
+COMPUTE_TYPE=auto
+
+# === Standalone Mode Configuration ===
+# Pipe-separated paths to scan
+LIBRARY_PATHS=/media/anime|/media/movies
+AUTO_SCAN_ENABLED=False
+SCAN_INTERVAL_MINUTES=30
+
+# Filter rules for standalone mode
+REQUIRED_AUDIO_LANGUAGE=ja
+REQUIRED_MISSING_SUBTITLE=spa
+SKIP_IF_SUBTITLE_EXISTS=True
+
+# === Provider Mode Configuration ===
+BAZARR_URL=http://bazarr:6767
+BAZARR_API_KEY=your_api_key_here
+PROVIDER_TIMEOUT_SECONDS=600
+PROVIDER_CALLBACK_ENABLED=True
+PROVIDER_POLLING_INTERVAL=30
+
+# === API Configuration ===
+WEBHOOK_PORT=9000
+API_HOST=0.0.0.0
 DEBUG=True
-CLEAR_VRAM_ON_COMPLETE=False
+
+# === Transcription Settings ===
+# Options: transcribe, translate
+TRANSCRIBE_OR_TRANSLATE=transcribe
+SUBTITLE_LANGUAGE_NAME=
+# Options: ISO_639_1, ISO_639_2_T, ISO_639_2_B, NAME, NATIVE
+SUBTITLE_LANGUAGE_NAMING_TYPE=ISO_639_2_B
+WORD_LEVEL_HIGHLIGHT=False
+CUSTOM_REGROUP=cm_sl=84_sl=42++++++1
+
+# === Skip Configuration ===
+SKIP_IF_EXTERNAL_SUBTITLES_EXIST=False
+SKIP_IF_TARGET_SUBTITLES_EXIST=True
+SKIP_IF_INTERNAL_SUBTITLES_LANGUAGE=eng
+# Pipe-separated language codes
+SKIP_SUBTITLE_LANGUAGES=
+SKIP_IF_AUDIO_LANGUAGES=
+SKIP_UNKNOWN_LANGUAGE=False
+SKIP_ONLY_SUBGEN_SUBTITLES=False
+
+# === Advanced Settings ===
+FORCE_DETECTED_LANGUAGE_TO=
+DETECT_LANGUAGE_LENGTH=30
+DETECT_LANGUAGE_OFFSET=0
+SHOULD_WHISPER_DETECT_AUDIO_LANGUAGE=False
+# Pipe-separated list in order of preference
+PREFERRED_AUDIO_LANGUAGES=eng
+
+# === Path Mapping ===
+USE_PATH_MAPPING=False
+PATH_MAPPING_FROM=/tv
+PATH_MAPPING_TO=/Volumes/TV
+
+# === Legacy SubGen Compatibility ===
+SHOW_IN_SUBNAME_SUBGEN=True
+SHOW_IN_SUBNAME_MODEL=True
 APPEND=False
+LRC_FOR_AUDIO_FILES=True