fix: defensive SDK response handling & parts-reader normalization

- Replace all response.data ?? [] with (response.data ?? response)
  pattern across 14 files to handle SDK array-shaped responses
- Normalize SDK parts in parts-reader.ts by injecting sessionID/
  messageID before validation (P1: SDK parts lack these fields)
- Treat unknown part types as having content in
  recover-empty-content-message-sdk.ts to prevent false placeholder
  injection on image/file parts
- Replace local isRecord with shared import in parts-reader.ts

src/hooks/session-recovery/recover-thinking-disabled-violation.ts

@@ -38,7 +38,7 @@ async function recoverThinkingDisabledViolationFromSDK(
 ): Promise<boolean> {
   try {
     const response = await client.session.messages({ path: { id: sessionID } })
-    const messages = (response.data ?? []) as MessageData[]
+    const messages = ((response.data ?? response) as unknown as MessageData[]) ?? []
 
     const messageIDsWithThinking: string[] = []
     for (const msg of messages) {