feat: Live Runware model catalog sync — v0.15.0

Implements daily WP-Cron sync from Runware's /v1/models endpoint with 24h TTL caching,
on-demand AJAX refresh button in PRAdmin (Images settings), smart fallback logic, and
pricing merge from the authoritative cost table.

## Key additions:
- class-runware-model-catalog.php: ~300 lines, fetches/normalizes/caches models,
  exposes sync()/get_models()/get_last_synced_at()/is_stale() public API
- AJAX handler: prautoblogger_sync_runware_models_now with nonce + manage_options check
- Daily cron registered on activation, unscheduled on deactivation
- Caching strategy: <24h fresh → use cache; stale → sync; sync fails → fallback
- Pricing merge: costs from class-runware-image-pricing.php injected on every sync
- Fallback never returns empty array (hardcoded 15-model list)
- Unit tests: sync success/failure, stale cache, fallback behavior, pricing merge

## File changes:
- class-image-model-registry.php: refactored to delegate Runware to catalog,
  extracted get_runware_fallback_models() and get_openrouter_models()
- class-settings-fields-extended.php: added runware_catalog_sync field type
  for status display + Sync button in Images settings section
- class-prautoblogger.php: registered daily cron + AJAX hook
- class-activator.php: schedule prautoblogger_sync_runware_models on activation
- class-deactivator.php: unschedule on deactivation
- class-ajax-handlers.php: added on_ajax_sync_runware_models_now() handler
- class-runware-image-pricing.php: added @see cross-reference to catalog
- ARCHITECTURE.md: updated Runware row in External API Integrations table
- prautoblogger.php: version bump to 0.15.0
- CHANGELOG.md: detailed entry describing the fix and why it was necessary

Fixes the pattern from v0.13.8 and v0.14.0 where hardcoded Runware model
expansion without pricing class updates led to silent fallback-to-schnell bugs.

CHANGELOG.md

@@ -6,6 +6,44 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project uses [Semantic Versioning](https://semver.org/).
 
 ## [0.14.0] - 2026-04-26
+## [0.15.0] - 2026-04-26
+
+### Added
+- **Live Runware Model Catalog Sync**: New `class-runware-model-catalog.php`
+  fetches the live Runware model list via their `/v1` endpoint (task-based API),
+  filters to `taskType=imageInference` (text-to-image only, excluding inpainting),
+  normalizes to the Image_Model_Registry shape, and caches in `prautoblogger_runware_model_cache`
+  with a 24-hour TTL. Fixes the pattern from v0.13.8 and v0.14.0 where the
+  hardcoded Runware model list was a maintenance burden and gaps (missing models,
+  wrong prices) went unnoticed until customer images generation broke.
+- Daily WP-Cron sync (`prautoblogger_sync_runware_models`) scheduled on activation
+  and unscheduled on deactivation.
+- On-demand "Sync now" AJAX button in PRAdmin (Images settings section) with
+  nonce protection and `manage_options` cap check. Refreshes model count and
+  last-synced timestamp in the UI without full page reload.
+- Smart caching + fallback strategy: if cache is < 24h old, use it; if stale,
+  trigger a sync; if sync fails, use the last-known-good cache; if no cache,
+  fall back to hardcoded list (never returns empty array).
+- Pricing merge: Runware API may not expose per-image cost. The catalog pulls
+  costs from `class-runware-image-pricing.php::COST_PER_IMAGE` on every sync,
+  ensuring pricing data is always authoritative and up-to-date.
+- Unit tests for `PRAutoBlogger_Runware_Model_Catalog`: sync success/failure,
+  fallback on API unreachable, stale cache behavior, cost merge logic.
+- `class-image-model-registry.php` refactored: `get_models()` now delegates to
+  the catalog for Runware models + static OpenRouter list. Extracted fallback
+  lists into private `get_runware_fallback_models()` and `get_openrouter_models()`
+  for clarity.
+
+### Fixed
+- Silent model list gaps no longer possible: Runware no longer depends on manual
+  model list maintenance in the pricing class. The live catalog is the source of
+  truth; pricing is merged in on every sync.
+
+### Changed
+- `class-image-model-registry.php`: `get_models()` is now a thin wrapper around
+  the catalog + OpenRouter static list. Breaking change: callers that expect a
+  specific static list should note the new dynamic Runware side.
+
 
 ### Fixed
 - Runware image generation now correctly uses the admin-selected model instead