Add debug logging for ANSI carryover events

src/server.ts

@@ -556,8 +556,10 @@ const server = Bun.serve<SessionData>({
           // Determine if new tail is an incomplete control sequence and split
           const [body, carry] = splitAnsiCarryover(combined);
           if (carry) {
+            console.debug(`Session ${sessionId}: ANSI carryover detected (${carry.length} bytes)`);
             ansiCarryovers.set(sessionId, carry);
           } else if (prevCarry) {
+            console.debug(`Session ${sessionId}: ANSI carryover resolved`);
             // Clear carry if previously set and now resolved
             ansiCarryovers.delete(sessionId);
           }