feat: NCWF-5/6/7/8/9 chess analysis page and engine integration

- NCWF-5: scaffold /analysis route with ChessBoard viewer and navigation
- NCWF-6: FEN / PGN / Game-ID input form with depth selector
- NCWF-7: extend GameApiService with analyzePosition(); add AnalysisService
  with game-wide annotation pipeline; proxy /api/analysis -> :8087
- NCWF-8: EvalTimelineComponent — SVG win-chance chart per ply
- NCWF-9: AnnotatedMoveListComponent — quality labels (!! ! ?! ? ??)
  derived from win-chance delta

Also fix pre-existing app.spec.ts failure (missing provideHttpClient).
Apply project-wide prettier formatting pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/pages/challenges/challenges.component.css

@@ -2,7 +2,14 @@
 
 .challenges-container {
   min-height: 100vh;
-  background: linear-gradient(135deg, #04000f 0%, #0e0235 25%, #2d0860 50%, #0e0235 75%, #04000f 100%);
+  background: linear-gradient(
+    135deg,
+    #04000f 0%,
+    #0e0235 25%,
+    #2d0860 50%,
+    #0e0235 75%,
+    #04000f 100%
+  );
   color: #e0e0e0;
   padding: 20px;
   font-family: 'Space Mono', 'Courier New', monospace;