Fix response parsing in GeminiClient that caused i2i to fail with
"No images generated" while t2i worked correctly.
- Remove aggressive chunk filtering that skipped chunks without
/gg-dl/ markers when status < 3, which missed valid i2i image data
- Add fallback candidate search at alternate indices [3, 4, 5] when
index [4] is empty, handling different i2i response structures
- Expand find_image_container search range and improve handling of
dict-based candidates from gemini-3-pro model
Anush
e455f2a924