feat(config): add MosaicConfig schema + loader with tier auto-detection

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

pnpm-lock.yaml

@@ -62,6 +62,9 @@ importers:
       '@mosaic/brain':
         specifier: workspace:^
         version: link:../../packages/brain
+      '@mosaic/config':
+        specifier: workspace:^
+        version: link:../../packages/config
       '@mosaic/coord':
         specifier: workspace:^
         version: link:../../packages/coord
@@ -351,6 +354,25 @@ importers:
         specifier: ^2.0.0
         version: 2.1.9(@types/node@22.19.15)(jsdom@29.0.0(@noble/hashes@2.0.1))(lightningcss@1.31.1)
 
+  packages/config:
+    dependencies:
+      '@mosaic/memory':
+        specifier: workspace:^
+        version: link:../memory
+      '@mosaic/queue':
+        specifier: workspace:^
+        version: link:../queue
+      '@mosaic/storage':
+        specifier: workspace:^
+        version: link:../storage
+    devDependencies:
+      typescript:
+        specifier: ^5.8.0
+        version: 5.9.3
+      vitest:
+        specifier: ^2.0.0
+        version: 2.1.9(@types/node@24.12.0)(jsdom@29.0.0(@noble/hashes@2.0.1))(lightningcss@1.31.1)
+
   packages/coord:
     dependencies:
       '@mosaic/types':