Simplify: one abstract base class per layer

- BaseKVStorage / BaseEventStorage / BaseDocumentStorage define the API once;
  implementations provide only raw primitives (client and server share an API)
- Drop KV indexes, query planner, unique indexes; document stores take index fields
- Escape every char <= '/' so child keys stay contiguous; skip-scan is now simple
- Event-sourced documents = event storage + any document store for projections
- New folder layout (kv-storage, event-storage, document-storage, utils); tests only in test/

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017Qxbkp4tA7G5SCWjzWuxmE

package.json

@@ -12,26 +12,6 @@
     ".": {
       "types": "./dist/index.d.ts",
       "import": "./dist/index.js"
-    },
-    "./kv": {
-      "types": "./dist/kv/index.d.ts",
-      "import": "./dist/kv/index.js"
-    },
-    "./events": {
-      "types": "./dist/events/index.d.ts",
-      "import": "./dist/events/index.js"
-    },
-    "./documents": {
-      "types": "./dist/documents/index.d.ts",
-      "import": "./dist/documents/index.js"
-    },
-    "./http": {
-      "types": "./dist/http/index.d.ts",
-      "import": "./dist/http/index.js"
-    },
-    "./testing": {
-      "types": "./dist/testing/index.d.ts",
-      "import": "./dist/testing/index.js"
     }
   },
   "files": [
@@ -53,13 +33,5 @@
     "prettier": "^3.9.10",
     "typescript": "^5.9.3",
     "vitest": "^3.2.7"
-  },
-  "peerDependencies": {
-    "vitest": ">=3"
-  },
-  "peerDependenciesMeta": {
-    "vitest": {
-      "optional": true
-    }
   }
 }