feat(build-and-exports-validation): validate build pipeline, exports map, and tsup config

All acceptance criteria verified:
- npm run build produces correct ESM + CJS + declarations
- npm run lint (tsc --noEmit) passes
- package.json exports map correct for index and event-target-redis
- tsup.config.ts lists all entry points
- src/index.ts barrel re-exports all modules
- Peer deps (ioredis optional) correct
- No runtime dependencies

tasks/016-build-and-exports-validation.md

@@ -1,7 +1,7 @@
 ---
 id: build-and-exports-validation
 name: Validate build, package.json exports, and tsup config for all adapters
-status: pending
+status: completed
 depends_on: []
 scope: narrow
 risk: low
@@ -38,8 +38,33 @@ This task validates the current setup and serves as a checklist item for each ad
 
 ## Notes
 
-> To be filled by implementation agent
+Validated all acceptance criteria. No changes were needed — the existing configuration is correct.
+
+### Validation Results
+
+1. **`npm run build` produces correct output** ✅
+   - `src/index.ts` → `dist/index.js` (ESM), `dist/index.cjs` (CJS), `dist/index.d.ts` + `dist/index.d.cts` (declarations)
+   - `src/event-target-redis.ts` → `dist/event-target-redis.js` (ESM), `dist/event-target-redis.cjs` (CJS), `dist/event-target-redis.d.ts` + `dist/event-target-redis.d.cts` (declarations)
+   - Code splitting enabled: shared chunk between entries
+   - Verified both ESM dynamic import and CJS require work for both entry points
+
+2. **`npm run lint` (tsc --noEmit) passes** ✅
+3. **`package.json` exports map has correct ESM/CJS/dts paths** ✅
+4. **`tsup.config.ts` lists all current entry points** ✅
+5. **`src/index.ts` re-exports everything from all modules** ✅
+6. **Peer dependencies and peerDependenciesMeta are correct** ✅
+7. **No runtime dependencies** ✅
+
+### Verified type resolution
+- Sub-path and barrel imports resolve correctly with tsc
+- Works with both skipLibCheck true and false
+
+### Verified package contents
+- `npm pack --dry-run` shows 19 files (all dist files + package.json)
 
 ## Summary
 
-> To be filled on completion
+Validated build pipeline, package.json exports map, and tsup config for all adapters. All acceptance criteria pass with no changes required.
+- Created: none
+- Modified: tasks/016-build-and-exports-validation.md (status update only)
+- Tests: 0 (no test files exist yet)