Fix ICE candidate handling - include sdpMid and sdpMLineIndex

- Update IceCandidate interface to include sdpMid and sdpMLineIndex fields
- Update SQLite and D1 storage to store full ICE candidate data
- Update server API to accept and return complete candidate objects
- This fixes the 'Either sdpMid or sdpMLineIndex must be specified' error

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

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

src/storage/d1.ts

@@ -59,6 +59,8 @@ export class D1Storage implements Storage {
         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,
         created_at INTEGER NOT NULL,
         FOREIGN KEY (offer_id) REFERENCES offers(id) ON DELETE CASCADE
       );
@@ -242,14 +244,26 @@ export class D1Storage implements Storage {
     offerId: string,
     peerId: string,
     role: 'offerer' | 'answerer',
-    candidates: string[]
+    candidates: Array<{
+      candidate: string;
+      sdpMid?: string | null;
+      sdpMLineIndex?: number | null;
+    }>
   ): Promise<number> {
     // D1 doesn't have transactions, so insert one by one
-    for (const candidate of candidates) {
+    for (const cand of candidates) {
       await this.db.prepare(`
-        INSERT INTO ice_candidates (offer_id, peer_id, role, candidate, created_at)
+        INSERT INTO ice_candidates (offer_id, peer_id, role, candidate, sdp_mid, sdp_m_line_index, created_at)
-        VALUES (?, ?, ?, ?, ?)
+        VALUES (?, ?, ?, ?, ?, ?, ?)
-      `).bind(offerId, peerId, role, candidate, Date.now()).run();
+      `).bind(
+        offerId,
+        peerId,
+        role,
+        cand.candidate,
+        cand.sdpMid ?? null,
+        cand.sdpMLineIndex ?? null,
+        Date.now()
+      ).run();
     }
 
     return candidates.length;
@@ -286,6 +300,8 @@ export class D1Storage implements Storage {
       peerId: row.peer_id,
       role: row.role,
       candidate: row.candidate,
+      sdpMid: row.sdp_mid,
+      sdpMLineIndex: row.sdp_m_line_index,
       createdAt: row.created_at,
     }));
   }

src/storage/sqlite.ts

@@ -56,6 +56,8 @@ export class SQLiteStorage implements Storage {
         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,
         created_at INTEGER NOT NULL,
         FOREIGN KEY (offer_id) REFERENCES offers(id) ON DELETE CASCADE
       );
@@ -252,16 +254,28 @@ export class SQLiteStorage implements Storage {
     offerId: string,
     peerId: string,
     role: 'offerer' | 'answerer',
-    candidates: string[]
+    candidates: Array<{
+      candidate: string;
+      sdpMid?: string | null;
+      sdpMLineIndex?: number | null;
+    }>
   ): Promise<number> {
     const stmt = this.db.prepare(`
-      INSERT INTO ice_candidates (offer_id, peer_id, role, candidate, created_at)
+      INSERT INTO ice_candidates (offer_id, peer_id, role, candidate, sdp_mid, sdp_m_line_index, created_at)
-      VALUES (?, ?, ?, ?, ?)
+      VALUES (?, ?, ?, ?, ?, ?, ?)
     `);
 
-    const transaction = this.db.transaction((candidates: string[]) => {
+    const transaction = this.db.transaction((candidates: typeof candidates) => {
-      for (const candidate of candidates) {
+      for (const cand of candidates) {
-        stmt.run(offerId, peerId, role, candidate, Date.now());
+        stmt.run(
+          offerId,
+          peerId,
+          role,
+          cand.candidate,
+          cand.sdpMid ?? null,
+          cand.sdpMLineIndex ?? null,
+          Date.now()
+        );
       }
     });
 
@@ -297,6 +311,8 @@ export class SQLiteStorage implements Storage {
       peerId: row.peer_id,
       role: row.role,
       candidate: row.candidate,
+      sdpMid: row.sdp_mid,
+      sdpMLineIndex: row.sdp_m_line_index,
       createdAt: row.created_at,
     }));
   }

src/storage/types.ts

@@ -23,6 +23,8 @@ export interface IceCandidate {
   peerId: string;
   role: 'offerer' | 'answerer';
   candidate: string;
+  sdpMid: string | null;
+  sdpMLineIndex: number | null;
   createdAt: number;
 }
 
@@ -125,14 +127,18 @@ export interface Storage {
    * @param offerId Offer identifier
    * @param peerId Peer ID posting the candidates
    * @param role Role of the peer (offerer or answerer)
-   * @param candidates Array of ICE candidate strings
+   * @param candidates Array of ICE candidate objects
    * @returns Number of candidates added
    */
   addIceCandidates(
     offerId: string,
     peerId: string,
     role: 'offerer' | 'answerer',
-    candidates: string[]
+    candidates: Array<{
+      candidate: string;
+      sdpMid?: string | null;
+      sdpMLineIndex?: number | null;
+    }>
   ): Promise<number>;
 
   /**