Fix WebGL page readiness gating

scripts/check-webgl-book-lab.js

@@ -189,7 +189,7 @@ const checks = [
     ['texture renderer publishes both spread sides for reveal preparation and fallback start', /this\.drawSpread\(this\.currentSpread \|\| this\.pagination\?\.getCurrentSpread\?\.\(\), \['left', 'right'\]\)/.test(textureRendererSource) && /const sides = \['left', 'right'\]/.test(textureRendererSource) && /pageMeta: prepared\.pageMeta \|\| \{\}/.test(textureRendererSource)],
     ['texture renderer marks page canvases with content versions before cache writes', /pageContentVersions/.test(textureRendererSource) && /buildPublishPageMeta/.test(textureRendererSource) && /completenessScore: \(maxBlockId \* 1000\) \+ lineCount/.test(textureRendererSource)],
     ['texture store queues newer same-page cache writes instead of dropping them', /storePageCanvas/.test(webglPageCacheSource) && /isOlderPageMeta/.test(webglPageCacheSource) && /const previousWrite = pending\?\.promise \|\| Promise\.resolve\(\)/.test(webglPageCacheSource) && /pendingPageWrites\.set\(key, \{[\s\S]*pageMeta: \{ \.\.\.\(pageMeta \|\| \{\}\) \}/.test(webglPageCacheSource)],
-    ['webgl texture store resident cache rejects older page versions before direct reuse', /isOlderPageMeta/.test(webglPageCacheSource) && /getResidentTextureForMeta/.test(webglPageCacheSource) && /getResidentTextureForMeta\(pageMeta\)/.test(webglPageCacheSource)],
+    ['webgl texture store resident cache reuses newest page version for older readiness requests', /isOlderPageMeta/.test(webglPageCacheSource) && /getResidentTextureForMeta/.test(webglPageCacheSource) && /if \(!resident\) return null/.test(webglPageCacheSource) && !/if \(!resident \|\| this\.isOlderPageMeta\(pageMeta, resident\.pageMeta\)\) return null/.test(webglPageCacheSource)],
     ['webgl flip page is a two-sided body using paper-thickness constants', /flipPageBackSurface/.test(source) && /flipPageEdge/.test(source) && /new THREE\.Mesh\(geometry, \[\s*materials\.flipPageSurface,\s*materials\.flipPageBackSurface,\s*materials\.flipPageEdge\s*\]\)/.test(source) && /PROCEDURAL_BOOK\.SHEET_THICKNESS_MODEL/.test(source) && /geometry\.addGroup\(0, topIndices\.length, 0\)/.test(source)],
     ['webgl animated page front and back maps are independently switchable before animation starts', /materials\.flipPageBackSurface = materials\.flipPageSurface\.clone\(\)/.test(source) && /materials\.flipPageSurface\.map = sourceTexture/.test(source) && /materials\.flipPageBackSurface\.map = backTexture \|\| getBlankPageTexture\(\)/.test(source) && /flip\.sourceTexture = sourceTexture/.test(source) && /flip\.backTexture = backTexture \|\| getBlankPageTexture\(\)/.test(source)],
     ['webgl flip preflight exposes texture side and orientation invariants for browser tests', /lastFlipTexturePreflight/.test(source) && /sourceTextureMatchesBackTexture/.test(source) && /targetBackSide/.test(source) && /getRuntimeInvariants/.test(source)],
@@ -217,7 +217,7 @@ const checks = [
     ['3D display playback is owned by book playback timeline', /book-playback-timeline/.test(uiDisplayHandlerSource) && /playWebGLBookSentence/.test(uiDisplayHandlerSource) && /timeline\.playSentence\(sentence\)/.test(uiDisplayHandlerSource) && /if \(useWebGLBookReveal\) \{[\s\S]*await this\.playWebGLBookSentence\(sentence\);[\s\S]*this\.markBlockRendered\(sentence\.blockId\);[\s\S]*return null;/.test(uiDisplayHandlerSource)],
     ['sentence queue lookahead prepares 3D book timeline segments', /book-playback-timeline/.test(sentenceQueueSource) && /bookPlaybackTimeline\.prepareSentence\(sentence/.test(sentenceQueueSource) && /timelineSegment: segment/.test(sentenceQueueSource)],
     ['book playback timeline prewarms texture window before prepared playback and flips', /prewarmSegmentTextures/.test(bookPlaybackTimelineSource) && /pageCache\.prewarmNavigationWindow/.test(bookPlaybackTimelineSource) && /this\.prewarmSegmentTextures\(segment\)/.test(bookPlaybackTimelineSource) && /await this\.pageCache\?\.prewarmNavigationWindow/.test(bookPlaybackTimelineSource)],
-    ['book playback timeline enforces resident page textures before prepared playback', /assertSegmentReady/.test(bookPlaybackTimelineSource) && /collectRequiredPageMetas/.test(bookPlaybackTimelineSource) && /this\.pageCache\.ensurePageTexture\(meta/.test(bookPlaybackTimelineSource) && /timeline-cache-readiness-failed/.test(bookPlaybackTimelineSource)],
+    ['book playback timeline enforces resident page textures before prepared playback', /assertSegmentReady/.test(bookPlaybackTimelineSource) && /collectRequiredPageMetas/.test(bookPlaybackTimelineSource) && /collectTexturePlanPageMetas/.test(bookPlaybackTimelineSource) && /this\.pageCache\.ensurePageTexture\(meta/.test(bookPlaybackTimelineSource) && /timeline-cache-readiness-failed/.test(bookPlaybackTimelineSource) && !/spreads\.add\(currentSpread \+ 1\)/.test(bookPlaybackTimelineSource)],
     ['3D reveal start is controlled by the prepared timeline instead of texture events', /sentence\.webglRevealController = \(\) => this\.startRevealForSegment\(segment\)/.test(bookPlaybackTimelineSource) && /startPreparedRevealAnimation\?\.\(segment\.blockId, \{[\s\S]*publishEvent: false/.test(bookPlaybackTimelineSource) && /PlaybackCoordinator: WebGL playback requires a prepared timeline reveal controller/.test(playbackCoordinatorSource) && !/document\.dispatchEvent\(new CustomEvent\('book-texture:reveal-block'/.test(methodBody(playbackCoordinatorSource, 'scheduleWebGLReveal'))],
     ['webgl lab delegates right-page reveal commits to timeline owner', /BookPlaybackTimeline\?\.ownsPageFlipCommit === true/.test(source) && /handleRevealCommittedForPageFlip/.test(source)],
     ['webgl reveal clock explicitly freezes during physical flips', /pageRevealFreezeAt/.test(source) && /state\.startedAt \+= frozenMs/.test(source) && /activeRevealBlockStarts\.set\(blockId, Number\(value\) \+ frozenMs\)/.test(source)],