fix: emit TypeScript declarations alongside bundled JS

Add tsconfig.build.json that emits only declaration files into dist/,
so TypeScript consumers retain type information after the switch from
source to bundled JS entry points.

- Add tsconfig.build.json with emitDeclarationOnly + rootDir: ./src
- Update build script to run tsc -p tsconfig.build.json after bundling
- Add types field to package.json exports and top-level
- Include .d.ts condition in export map for both . and ./server

Addresses CodeRabbit review comment on PR #36

Author: bendtherules

package.json

@@ -29,8 +29,14 @@
     "eslint-plugin-jsdoc": "^50.6.11"
   },
   "exports": {
-    ".": "./dist/index.js",
-    "./server": "./dist/index.js"
+    ".": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    },
+    "./server": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
   },
   "files": [
     "dist/"
@@ -47,6 +53,7 @@
   "license": "MPL-2.0",
   "main": "dist/index.js",
   "module": "dist/index.js",
+  "types": "dist/index.d.ts",
   "name": "@devtheops/opencode-plugin-otel",
   "oc-plugin": [
     "server"
@@ -59,7 +66,7 @@
     "url": "https://github.com/DEVtheOPS/opencode-plugin-otel.git"
   },
   "scripts": {
-    "build": "bun build src/index.ts --outdir=./dist --target=node",
+    "build": "bun build src/index.ts --outdir=./dist --target=node && tsc -p tsconfig.build.json",
     "check:jsdoc-coverage": "bun scripts/check-jsdoc-coverage.mjs",
     "lint": "bun --bun eslint .",
     "typecheck": "tsc --noEmit",

tsconfig.build.json

@@ -0,0 +1,12 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": false,
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "outDir": "./dist",
+    "rootDir": "./src"
+  },
+  "include": ["src"],
+  "exclude": ["eslint.config.mjs", "dist", "scripts", "tests"]
+}