Refactor: Store ICE candidates as JSON objects

- Simplify storage by storing entire RTCIceCandidateInit as JSON
- Remove individual sdp_mid and sdp_m_line_index columns
- More future-proof and maintainable approach
- Recreated ice_candidates table in D1

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

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

src/storage/sqlite.ts

@@ -1,6 +1,6 @@
 import Database from 'better-sqlite3';
 import { randomUUID } from 'crypto';
-import { Storage, Offer, IceCandidate, CreateOfferRequest, TopicInfo } from './types.ts';
+import { Storage, Offer, IceCandidate, CreateOfferRequest, TopicInfo, RTCIceCandidateInit } from './types.ts';
 
 /**
  * SQLite storage adapter for topic-based offer management
@@ -55,9 +55,7 @@ export class SQLiteStorage implements Storage {
         offer_id TEXT NOT NULL,
         peer_id TEXT NOT NULL,
         role TEXT NOT NULL CHECK(role IN ('offerer', 'answerer')),
-        candidate TEXT NOT NULL,
-        sdp_mid TEXT,
-        sdp_m_line_index INTEGER,
+        candidate TEXT NOT NULL, -- JSON: RTCIceCandidateInit object
         created_at INTEGER NOT NULL,
         FOREIGN KEY (offer_id) REFERENCES offers(id) ON DELETE CASCADE
       );
@@ -254,26 +252,20 @@ export class SQLiteStorage implements Storage {
     offerId: string,
     peerId: string,
     role: 'offerer' | 'answerer',
-    candidates: Array<{
-      candidate: string;
-      sdpMid?: string | null;
-      sdpMLineIndex?: number | null;
-    }>
+    candidates: RTCIceCandidateInit[]
   ): Promise<number> {
     const stmt = this.db.prepare(`
-      INSERT INTO ice_candidates (offer_id, peer_id, role, candidate, sdp_mid, sdp_m_line_index, created_at)
-      VALUES (?, ?, ?, ?, ?, ?, ?)
+      INSERT INTO ice_candidates (offer_id, peer_id, role, candidate, created_at)
+      VALUES (?, ?, ?, ?, ?)
     `);
 
-    const transaction = this.db.transaction((candidates: typeof candidates) => {
+    const transaction = this.db.transaction((candidates: RTCIceCandidateInit[]) => {
       for (const cand of candidates) {
         stmt.run(
           offerId,
           peerId,
           role,
-          cand.candidate,
-          cand.sdpMid ?? null,
-          cand.sdpMLineIndex ?? null,
+          JSON.stringify(cand), // Store full object as JSON
           Date.now()
         );
       }
@@ -310,9 +302,7 @@ export class SQLiteStorage implements Storage {
       offerId: row.offer_id,
       peerId: row.peer_id,
       role: row.role,
-      candidate: row.candidate,
-      sdpMid: row.sdp_mid,
-      sdpMLineIndex: row.sdp_m_line_index,
+      candidate: JSON.parse(row.candidate), // Parse JSON back to object
       createdAt: row.created_at,
     }));
   }