Add Audible region config and user password change modal

Implements configurable Audible region selection in setup and admin settings, affecting all Audible API calls and triggering data refresh on change. Adds a user-facing 'Change Password' modal in the header for local users, moving password change from admin-only to all local users via a new /api/auth/change-password endpoint. Updates documentation, API routes, and context to support these features, and removes the old admin-only password change flow.

documentation/integrations/audible.md

@@ -19,6 +19,46 @@ Audiobook metadata from Audnexus API (primary) and Audible.com scraping (fallbac
 - Multiple selector strategies with promotional text filtering
 - Extract JSON-LD structured data when available
 
+## Region Configuration
+
+**Status:** ✅ Implemented
+
+Configurable Audible region for accurate metadata matching across different international Audible stores.
+
+**Supported Regions:**
+- United States (`us`) - `audible.com` (default)
+- Canada (`ca`) - `audible.ca`
+- United Kingdom (`uk`) - `audible.co.uk`
+- Australia (`au`) - `audible.com.au`
+- India (`in`) - `audible.in`
+
+**Why Regions Matter:**
+- Each Audible region uses different ASINs for the same audiobook
+- Metadata engines (Audnexus/Audible Agent) in Plex/Audiobookshelf must match RMAB's region
+- Mismatched regions cause poor search results and failed metadata matching
+
+**Configuration:**
+- Key: `audible.region` (stored in database)
+- Default: `us`
+- Set during: Setup wizard (Backend Selection step) or Admin Settings (Library tab)
+- Help text instructs users to match their metadata engine region
+
+**Implementation:**
+- `AudibleService` loads region from config on initialization
+- Dynamically builds base URL: `AUDIBLE_REGIONS[region].baseUrl`
+- Audnexus API calls include region parameter: `?region={code}`
+- IP redirect prevention: `?ipRedirectOverride=true` on all Audible requests
+- Configuration service helper: `getAudibleRegion()` returns configured region
+- **Auto-detection of region changes**: Service checks config before each request and re-initializes if region changed
+- **Cache clearing**: When region changes, ConfigService cache and AudibleService initialization are cleared
+- **Automatic refresh**: Changing region automatically triggers `audible_refresh` job to fetch new data
+
+**Files:**
+- Types: `src/lib/types/audible.ts`
+- Service: `src/lib/integrations/audible.service.ts`
+- Config: `src/lib/services/config.service.ts`
+- API: `src/app/api/admin/settings/audible/route.ts`
+
 ## Discovery Strategy (Popular/New/Search)
 
 - Parse Audible HTML with Cheerio
@@ -28,10 +68,15 @@ Audiobook metadata from Audnexus API (primary) and Audible.com scraping (fallbac
 
 ## Data Sources
 
-1. **Best Sellers:** `https://www.audible.com/adblbestsellers`
-2. **New Releases:** `https://www.audible.com/newreleases`
-3. **Search:** `https://www.audible.com/search?keywords={query}`
-4. **Detail Page:** `https://www.audible.com/pd/{asin}`
+URLs dynamically built based on configured region:
+
+1. **Best Sellers:** `{baseUrl}/adblbestsellers`
+2. **New Releases:** `{baseUrl}/newreleases`
+3. **Search:** `{baseUrl}/search?keywords={query}&ipRedirectOverride=true`
+4. **Detail Page:** `{baseUrl}/pd/{asin}?ipRedirectOverride=true`
+5. **Audnexus API:** `https://api.audnex.us/books/{asin}?region={code}`
+
+Where `{baseUrl}` is determined by configured region (e.g., `https://www.audible.co.uk` for UK).
 
 ## Metadata Extracted