fix: use glob matching for Gemini image MIME types

[huntcsg]

Problem

gemini-3-pro-image-preview nondeterministically returns image/jpeg instead of image/png in response inlineData. get_image_from_response() hardcodes get_parts_by_type(response, "image/png"), which silently drops JPEG responses and falls back to torch.zeros((1, 1024, 1024, 4)) — producing all-black (0,0,0,0 RGBA) output images.

Confirmed via API response logs: successful runs had mimeType: "image/png", failed (black) runs had mimeType: "image/jpeg". 100% correlation.

Fix

• Add _mime_matches() helper using fnmatch for glob-style MIME matching (e.g. "image/*" matches "image/png", "image/jpeg", "image/webp")
• Change get_parts_by_type() to use _mime_matches() instead of == for MIME comparison
• Change get_image_from_response() to request "image/*" instead of "image/png"

Uses mime.value (not str(mime)) to ensure correct behavior on Python 3.10 where str() on a str Enum returns "ClassName.member" instead of the value.

API Node PR Checklist

Scope

• Is API Node Change

Pricing & Billing

• Need pricing update
• No pricing update

If Need pricing update:

• Metronome rate cards updated
• Auto‑billing tests updated and passing

QA

• QA done
• QA not required

Comms

• Informed Kosinkadink