- Add 'amazon' to VALID_SOURCES (and transitively VALID_STREAM_SOURCES)
in core/search/orchestrator.py so the backend accepts it as a
requested source without returning 400
- Add resolve_client('amazon') case — mirrors musicbrainz pattern,
gets the cached AmazonClient from the metadata registry
- Add 'amazon' to _alternate_sources() so it appears as a tab when
another source is primary (always available, no credentials)
- Add SERVICE_CONFIG_REGISTRY entry 'amazon': {'always': True} so
/api/settings/config-status reports it as configured
- Add SOURCE_LABELS['amazon'] and SOURCE_ORDER entry in
shared-helpers.js so both enhanced search and global search show
the Amazon Music tab
- Add 'amazon' to _ALWAYS_CONFIGURED_SOURCES so the picker never
dims the tab (no credentials required)
- Add .enh-tab-amazon.active CSS (Amazon orange #FF9900)
- 3530 tests pass