Replace KV storage with D1, add peer_id field, simplify README

Storage changes:
- Remove KV storage adapter
- Add D1 storage adapter for Cloudflare Workers
- Update schema to use peer_id instead of info field
- Add database migrations for D1

Documentation:
- Simplify README to be more concise
- Update deployment instructions for D1
- Add D1_SETUP.md explaining migration from KV
- Update DEPLOYMENT.md with D1 setup steps

API changes:
- Replace info field with peerId in session creation
- Update all storage interfaces and implementations

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

D1_SETUP.md

@@ -0,0 +1,97 @@
+# D1 Database Setup
+
+This project uses Cloudflare D1 for storage instead of KV to avoid eventual consistency issues.
+
+## Local Development
+
+For local development, Wrangler automatically creates a local D1 database:
+
+```bash
+npx wrangler dev
+```
+
+## Production Setup
+
+### 1. Create the D1 Database
+
+```bash
+npx wrangler d1 create rondevu-sessions
+```
+
+This will output something like:
+
+```
+✅ Successfully created DB 'rondevu-sessions'
+
+[[d1_databases]]
+binding = "DB"
+database_name = "rondevu-sessions"
+database_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
+```
+
+### 2. Update wrangler.toml
+
+Copy the `database_id` from the output and update it in `wrangler.toml`:
+
+```toml
+[[d1_databases]]
+binding = "DB"
+database_name = "rondevu-sessions"
+database_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"  # Replace with your actual ID
+```
+
+### 3. Initialize the Database Schema
+
+```bash
+npx wrangler d1 execute rondevu-sessions --remote --file=./migrations/schema.sql
+```
+
+### 4. Deploy
+
+```bash
+npx wrangler deploy
+```
+
+## Database Migrations
+
+To run migrations on the remote database:
+
+```bash
+npx wrangler d1 execute rondevu-sessions --remote --file=./migrations/schema.sql
+```
+
+To run migrations on the local database:
+
+```bash
+npx wrangler d1 execute rondevu-sessions --local --file=./migrations/schema.sql
+```
+
+## Querying the Database
+
+### Remote Database
+
+```bash
+# List all sessions
+npx wrangler d1 execute rondevu-sessions --remote --command="SELECT * FROM sessions"
+
+# Count sessions
+npx wrangler d1 execute rondevu-sessions --remote --command="SELECT COUNT(*) FROM sessions"
+
+# Delete expired sessions
+npx wrangler d1 execute rondevu-sessions --remote --command="DELETE FROM sessions WHERE expires_at <= $(date +%s)000"
+```
+
+### Local Database
+
+Replace `--remote` with `--local` for local queries.
+
+## Why D1 Instead of KV?
+
+D1 provides:
+- **Strong consistency** - No race conditions from eventual consistency
+- **ACID transactions** - Atomic updates prevent data corruption
+- **SQL queries** - More powerful query capabilities
+- **Relational data** - Better for complex queries and joins
+- **No propagation delay** - Immediate read-after-write consistency
+
+KV's eventual consistency was causing race conditions where ICE candidate updates would overwrite answers with stale data.