chore(prompts-core): register workspace package

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

packages/prompts-core/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "@oh-my-opencode/prompts-core",
+  "version": "0.1.0",
+  "type": "module",
+  "private": true,
+  "description": "Pure TypeScript prompt loading and variant resolution core for oh-my-opencode.",
+  "exports": {
+    ".": {
+      "types": "./index.d.ts",
+      "import": "./src/index.ts"
+    }
+  },
+  "types": "./index.d.ts",
+  "scripts": {
+    "typecheck": "tsgo --noEmit -p tsconfig.json",
+    "test": "bun test src/*.test.ts test/*.test.ts"
+  },
+  "dependencies": {
+    "@oh-my-opencode/utils": "workspace:*"
+  }
+}

packages/prompts-core/tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "ESNext",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "lib": ["ESNext"],
+    "types": ["bun-types"]
+  },
+  "include": ["src/**/*", "test/**/*"]
+}