Preserve preview harness, editor, email and task improvements

Snapshot current maintainer-preview application changes and regression fixtures for integration into lab. Excludes local runtime data, evaluation outputs and source backups. Focused Python regression selection: 140 passed; full suite not certified.

src/image_model_ids.py

@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+import math
+
 
 _IMAGE_MODEL_PREFIXES = (
     "gpt-image",
@@ -23,6 +25,21 @@ def model_id_leaf(model_id: str) -> str:
     return str(model_id or "").strip().split("/")[-1].lower()
 
 
+def image_edit_size(model_id: str, width: int, height: int) -> str:
+    """Match source geometry within the fixed GPT Image 1 output sizes."""
+    if width <= 0 or height <= 0:
+        raise ValueError("Image dimensions must be positive")
+    leaf = model_id_leaf(model_id)
+    if leaf in {"gpt-image-1", "gpt-image-1-mini", "gpt-image-1.5",
+                "gpt-5-image", "gpt-5-image-mini"}:
+        sizes = ((1024, 1024), (1536, 1024), (1024, 1536))
+        width, height = min(sizes, key=lambda candidate: (
+            abs(math.log((candidate[0] / candidate[1]) / (width / height))),
+            abs(candidate[0] * candidate[1] - width * height),
+        ))
+    return f"{width}x{height}"
+
+
 def looks_like_image_generation_model(model_id: str) -> bool:
     """Return True when a model id should use image generation routes.
 
@@ -38,5 +55,6 @@ def looks_like_image_generation_model(model_id: str) -> bool:
         return True
     # Newer OpenAI image models use names like gpt-5-image instead of
     # gpt-image-1. Keep this pattern provider-agnostic.
-    return leaf.startswith("gpt-") and "-image" in leaf
-
+    return (leaf.startswith("gpt-") and "-image" in leaf) or (
+        leaf.startswith("gemini-") and "image" in leaf
+    )