fix: address 5 SDK compatibility issues from Cubic round 8

- P1: Use compacted timestamp check instead of nonexistent truncated
  field in target-token-truncation.ts
- P1: Use defensive (response.data ?? response) pattern in
  hook-message-injector/injector.ts to match codebase convention
- P2: Filter by tool type in countTruncatedResultsFromSDK to avoid
  counting non-tool compacted parts
- P2: Treat thinking/meta-only messages as empty in both
  empty-content-recovery-sdk.ts and message-builder.ts to align
  SDK path with file-based logic

src/hooks/anthropic-context-window-limit-recovery/tool-result-storage-sdk.ts

@@ -104,7 +104,7 @@ export async function countTruncatedResultsFromSDK(
     for (const msg of messages) {
       if (!msg.parts) continue
       for (const part of msg.parts) {
-        if (part.state?.time?.compacted) count++
+        if (part.type === "tool" && part.state?.time?.compacted) count++
       }
     }