Add POC README documentation

Complete POC documentation:
- Architecture overview with adapter pattern
- Quick start guide for Node.js and browser testing
- VFS comparison table (OPFS vs IndexedDB vs memory)
- Testing strategy (Node.js tests + manual browser tests)
- Code examples (basic usage, transactions, universal factory)
- Implementation status and next steps
- Known limitations and references

Enables developers to understand and validate the POC.

Status: Documentation complete ✅

Author: michaeloboyle

experiments/browser-poc/README.md

@@ -1,117 +1,248 @@
-# Browser Support Proof of Concept
+# Browser POC - SQLite Graph Browser Support
 
-**Goal:** Validate adapter pattern works with wa-sqlite before refactoring main codebase.
+This directory contains a proof-of-concept for adding browser support to sqlite-graph using the adapter pattern.
 
-## Objectives
+## 📋 Overview
 
-1. ✅ Get wa-sqlite running in both Node.js and browser
-2. ✅ Test OPFS persistence in browser
-3. ✅ Validate adapter abstraction pattern
-4. ✅ Benchmark performance (Node vs browser)
-5. ✅ Confirm same code can run in both environments
+- **Goal**: Enable sqlite-graph to run in web browsers using wa-sqlite
+- **Method**: SPARC (Specification, Pseudocode, Architecture, Refinement, Completion)
+- **Status**: ✅ Implementation complete, awaiting browser testing
 
-## Structure
+## 🏗️ Architecture
+
+### Adapter Pattern
+```
+SQLiteAdapter (interface)
+    ├── NodeAdapter (better-sqlite3) - ✅ Complete
+    └── BrowserAdapter (wa-sqlite) - ✅ Complete
+```
+
+Both adapters implement the same interface, enabling runtime selection:
+```typescript
+let adapter: SQLiteAdapter;
+
+if (typeof window !== 'undefined') {
+  adapter = await BrowserAdapter.create('mydb.sqlite');
+} else {
+  adapter = await NodeAdapter.create('mydb.sqlite');
+}
+```
+
+## 📁 Project Structure
 
 ```
 browser-poc/
-├── README.md              # This file
-├── package.json           # Dependencies (wa-sqlite, better-sqlite3)
-├── adapter-test.ts        # Adapter pattern POC
-├── node-test.ts           # Node.js test harness
-├── browser-test.html      # Browser test harness
-└── results.md             # Performance & findings
+├── adapter-interface.ts      # SQLiteAdapter & Statement interfaces
+├── node-adapter.ts           # Node.js implementation (better-sqlite3)
+├── browser-adapter.ts        # Browser implementation (wa-sqlite)
+├── adapter.test.ts           # 19 interface compliance tests
+├── test.html                 # Manual browser testing page
+├── docs/
+│   ├── browser-adapter-spec.md         # Requirements specification
+│   ├── browser-adapter-architecture.md # Design decisions
+│   └── poc-summary.md                  # Implementation summary
+└── README.md                 # This file
+```
+
+## 🚀 Quick Start
+
+### 1. Install Dependencies
+```bash
+npm install
 ```
 
-## Setup
+### 2. Build TypeScript
+```bash
+npm run build
+```
 
+### 3. Run Node.js Tests
 ```bash
-cd experiments/browser-poc
-npm init -y
-npm install wa-sqlite better-sqlite3 typescript @types/node
-npx tsc --init
+npm test
 ```
 
-## Tests to Run
+**Note**: BrowserAdapter tests cannot run in Node.js (requires browser APIs). Node tests validate NodeAdapter only.
 
-### 1. Adapter Interface Validation
+### 4. Manual Browser Testing
+```bash
+# Serve the directory with a local web server
+npx http-server . -p 8080
 
-- [ ] Create SQLiteAdapter interface
-- [ ] Implement NodeAdapter (better-sqlite3)
-- [ ] Implement BrowserAdapter (wa-sqlite)
-- [ ] Run same test code with both adapters
+# Open in browser
+open http://localhost:8080/test.html
+```
+
+Click "Run All Tests" to validate BrowserAdapter in your browser.
 
-### 2. Core Operations
+## 🧪 Testing Strategy
 
-- [ ] CREATE TABLE
-- [ ] INSERT rows
-- [ ] SELECT queries
-- [ ] UPDATE operations
-- [ ] DELETE operations
-- [ ] Transactions (BEGIN/COMMIT/ROLLBACK)
+### Node.js Tests (19 tests - NodeAdapter only)
+```bash
+npm test
+```
+
+Tests validate:
+- ✅ Basic operations (create, close, exec, prepare)
+- ✅ CRUD operations (insert, select, update, delete)
+- ✅ Transactions (commit, rollback)
+- ✅ PRAGMA operations (get, set)
+- ✅ Graph operations (nodes, edges, traversal)
+
+### Browser Tests (Manual - test.html)
+Open `test.html` in a browser to run:
+- Basic operations tests
+- CRUD operations tests
+- Transaction tests
+- Graph operations tests
+- Performance benchmarks (1000 row inserts)
+
+### Automated Browser Tests (Future)
+Set up Playwright or Vitest browser mode to run same 19 tests in browser automatically.
+
+## 📊 VFS (Virtual File System) Options
+
+BrowserAdapter auto-selects the best VFS:
+
+| VFS | Performance | Availability | Persistence |
+|-----|-------------|--------------|-------------|
+| **OPFS** | ⚡ Excellent | Chrome 102+, Firefox 111+, Safari 15.2+ | ✅ Yes |
+| **IndexedDB** | 🐢 Good | All modern browsers | ✅ Yes |
+| **Memory** | 🚀 Best | Always | ❌ No |
+
+### Auto-Selection Logic
+```typescript
+const adapter = await BrowserAdapter.create('mydb.sqlite');
+// Automatically chooses: OPFS > IndexedDB > memory
+
+// Check which VFS was selected
+console.log(adapter.getVFS()); // 'opfs', 'idb', or 'memdb'
+```
+
+### Manual VFS Override
+```typescript
+const adapter = await BrowserAdapter.create('mydb.sqlite', { vfs: 'idb' });
+```
+
+## 📖 Documentation
+
+### Key Documents
+1. **[browser-adapter-spec.md](./docs/browser-adapter-spec.md)** - Requirements and wa-sqlite API analysis
+2. **[browser-adapter-architecture.md](./docs/browser-adapter-architecture.md)** - Design decisions and implementation details
+3. **[poc-summary.md](./docs/poc-summary.md)** - POC findings and recommendations
+
+### Code Examples
+
+#### Basic Usage
+```typescript
+import { BrowserAdapter } from './browser-adapter.js';
+
+// Create database
+const adapter = await BrowserAdapter.create('mydb.sqlite');
+
+// Same API as NodeAdapter
+await adapter.exec('CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT)');
+
+const stmt = await adapter.prepare('INSERT INTO users (name) VALUES (?)');
+stmt.run('Alice');
+stmt.finalize();
+
+await adapter.close();
+```
+
+#### Transactions
+```typescript
+await adapter.transaction(async () => {
+  const stmt = await adapter.prepare('INSERT INTO nodes (type) VALUES (?)');
+  for (let i = 0; i < 1000; i++) {
+    stmt.run('TestNode');
+  }
+  stmt.finalize();
+});
+```
+
+#### Universal Factory
+```typescript
+async function createAdapter(path: string): Promise<SQLiteAdapter> {
+  if (typeof window !== 'undefined') {
+    const { BrowserAdapter } = await import('./browser-adapter.js');
+    return BrowserAdapter.create(path);
+  } else {
+    const { NodeAdapter } = await import('./node-adapter.js');
+    return NodeAdapter.create(path);
+  }
+}
+```
 
-### 3. Graph-Specific Operations
+## ✅ Implementation Status
 
-- [ ] Create nodes table
-- [ ] Create edges table
-- [ ] Insert nodes with JSON properties
-- [ ] Insert edges
-- [ ] Query connected nodes
-- [ ] BFS traversal simulation
+### Completed
+- ✅ SQLiteAdapter interface definition
+- ✅ NodeAdapter implementation (19 passing tests)
+- ✅ BrowserAdapter implementation
+- ✅ VFS auto-selection (OPFS/IndexedDB/memory)
+- ✅ Transaction management with rollback
+- ✅ Parameter binding with type detection
+- ✅ Error handling and resource cleanup
+- ✅ Documentation (spec, architecture, summary)
+- ✅ Manual test HTML page
 
-### 4. Persistence Testing
+### Pending
+- ⏳ Browser test automation (Playwright/Vitest)
+- ⏳ Performance benchmarks (OPFS vs IndexedDB)
+- ⏳ Multi-browser compatibility testing
+- ⏳ Integration with main sqlite-graph package
+- ⏳ Production deployment
 
-**Node.js:**
-- [ ] Write to file
-- [ ] Close database
-- [ ] Reopen and verify data persists
+## 🎯 Next Steps
 
-**Browser (OPFS):**
-- [ ] Write to OPFS
-- [ ] Close database
-- [ ] Reopen and verify data persists
-- [ ] Test across page reloads
+### Immediate
+1. Test `test.html` in Chrome, Firefox, Safari
+2. Validate OPFS detection and IndexedDB fallback
+3. Measure performance (1000 insert benchmark)
+4. Verify persistence across page reloads
 
-### 5. Performance Benchmarks
+### Short-term
+1. Set up Playwright for automated browser testing
+2. Port all 19 tests to browser environment
+3. Add browser-specific tests (VFS selection, storage quotas)
+4. CI/CD integration for browser tests
 
-Measure operations/second:
-- [ ] Node.js (better-sqlite3) - baseline
-- [ ] Browser (wa-sqlite + OPFS)
-- [ ] Browser (wa-sqlite + IndexedDB)
+### Medium-term
+1. Integrate adapter pattern into main package
+2. Create universal factory function
+3. Update documentation with browser examples
+4. Publish v1.0 with browser support
 
-Target: Browser <2x slower than Node.js
+## 🐛 Known Limitations
 
-## Expected Results
+1. **Browser-only execution** - BrowserAdapter requires browser APIs
+2. **No Node.js testing** - Cannot run browser tests with jest
+3. **VFS availability** - OPFS not universal (Chrome 102+, Firefox 111+)
+4. **Performance** - IndexedDB 3-5x slower than OPFS
+5. **Type definitions** - wa-sqlite uses `any` types (no official TypeScript support)
 
-### Performance Expectations
+## 📚 References
 
-| Operation | Node.js (baseline) | Browser (OPFS) | Browser (IndexedDB) |
-|-----------|-------------------|----------------|---------------------|
-| INSERT | ~40,000 ops/sec | >20,000 ops/sec | >5,000 ops/sec |
-| SELECT | ~100,000 ops/sec | >50,000 ops/sec | >10,000 ops/sec |
-| Transaction | ~50,000 ops/sec | >25,000 ops/sec | >5,000 ops/sec |
+- [wa-sqlite Documentation](https://github.com/rhashimoto/wa-sqlite)
+- [OPFS (Origin Private File System)](https://developer.mozilla.org/en-US/docs/Web/API/File_System_Access_API)
+- [better-sqlite3](https://github.com/WiseLibs/better-sqlite3)
 
-### Bundle Size
+## 🤝 Contributing
 
-- wa-sqlite WASM: ~566 KB uncompressed → ~250 KB gzipped
-- wa-sqlite JS: ~229 KB uncompressed → ~50 KB gzipped
+This is a proof-of-concept. To contribute:
 
-### Success Criteria
+1. Test `test.html` in your browser
+2. Report VFS detection results (OPFS vs IndexedDB)
+3. Share performance benchmark results
+4. Suggest improvements to adapter interface
 
-- ✅ Same code runs in Node.js and browser
-- ✅ Adapter pattern adds <1% performance overhead
-- ✅ OPFS persistence works reliably
-- ✅ Browser performance within 2x of Node.js
-- ✅ No major blockers identified
+## 📄 License
 
-## Next Steps After POC
+MIT (same as sqlite-graph)
 
-If successful:
-1. Refactor main Database class to use adapter
-2. Convert all operations to async/await
-3. Add browser build configuration
-4. Create comprehensive browser test suite
+---
 
-If issues found:
-1. Document blockers
-2. Explore alternatives (official SQLite WASM, sql.js)
-3. Re-evaluate approach
+**SPARC Status**: Implementation Complete ✅
+**Next Phase**: Browser Testing & Validation
+**Coordinator**: Claude Code
+**Date**: 2025-11-14