feat: add SDK exports for consumer app integration

- Create standalone dist/sdk/ module with parseObservations, buildObservationPrompt, parseSummary
- Add package.json exports for 'claude-mem/sdk' and 'claude-mem/modes/*'
- Add TypeScript declarations

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package.json

@@ -26,6 +26,21 @@
     "url": "https://github.com/thedotmack/claude-mem/issues"
   },
   "type": "module",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    },
+    "./sdk": {
+      "types": "./dist/sdk/index.d.ts",
+      "import": "./dist/sdk/index.js"
+    },
+    "./modes/*": "./plugin/modes/*"
+  },
+  "files": [
+    "dist",
+    "plugin"
+  ],
   "engines": {
     "node": ">=18.0.0",
     "bun": ">=1.0.0"