Add gemini-3.1-flash-image-preview (Nano Banana 2) support

[ystknsh]

概要

画像生成モデル gemini-3.1-flash-image-preview（Nano Banana 2）のサポートを追加。

• src/tools/backend/types.ts - union 型に追加
• src/components/settings/ImageGenSettings.vue - UI の選択肢・型に追加
• src/views/HomeView.vue - 表示名の条件分岐に追加

参考

• https://ai.google.dev/gemini-api/docs/models/gemini-3.1-flash-image-preview

GitHub 検索結果

https://github.com/search?q=org%3Areceptron+gemini-3-pro-image-preview+OR+org%3Areceptron+gemini-2.5-flash-image++repo%3Areceptron%2FMulmoChat&type=code

Summary by CodeRabbit

• New Features
  • Added Gemini 3.1 Flash Image model as a new option for image generation settings.
  • Extended backend configuration to support the new model variant.
  • Updated the UI to properly display and handle the new Gemini model selection.

[coderabbitai]

📝 Walkthrough

Walkthrough

Support for a new Gemini image generation model "gemini-3.1-flash-image-preview" is added across the UI settings component, backend type definitions, and view display logic to recognize and handle the new model variant.

Changes

Cohort / File(s)	Summary
UI Settings Component src/components/settings/ImageGenSettings.vue	Added "gemini-3.1-flash-image-preview" to the Gemini Model select options and extended the modelValue union type to support emitting the new model selection.
Backend Type Definitions src/tools/backend/types.ts	Extended geminiModel type union in ImageGenerationConfigValue from two to three options, including the new "gemini-3.1-flash-image-preview" model.
View Logic src/views/HomeView.vue	Added conditional branch to recognize "gemini-3.1-flash-image-preview" and display "Gemini 3.1 Flash Image" as the image model name.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

A flash of light, so swift and new,
Three-point-one hops into our view,
The rabbit models, shiny bright,
Added 'cross the stack tonight! 🐰✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title accurately summarizes the main objective: adding support for a new Gemini image model (gemini-3.1-flash-image-preview).
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feature/add-gemini-3.1-flash-image-preview

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[coderabbitai]

🧹 Nitpick comments (1)

src/components/settings/ImageGenSettings.vue (1)

122-125: Prefer deriving Gemini model type from ImageGenerationConfigValue to avoid drift.

This cast duplicates literal unions already defined in backend types. Reusing the source type will reduce future miss-sync risk.

♻️ Suggested refactor

 const handleGeminiModelChange = (event: Event) => {
-  const geminiModel = (event.target as HTMLSelectElement).value as
-    | "gemini-2.5-flash-image"
-    | "gemini-3.1-flash-image-preview"
-    | "gemini-3-pro-image-preview";
+  const geminiModel = (event.target as HTMLSelectElement)
+    .value as NonNullable<ImageGenerationConfigValue["geminiModel"]>;
   emit("update:modelValue", {
     ...normalizedConfig.value,
     geminiModel,
   });
 };

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@src/components/settings/ImageGenSettings.vue` around lines 122 - 125, Replace
the hard-coded literal union cast on the geminiModel assignment with the
backend-derived type: import the ImageGenerationConfigValue type and cast (or
narrow) the event target value to the appropriate member/union from
ImageGenerationConfigValue (e.g., the model field or an Extract<> of
ImageGenerationConfigValue) instead of the inline `"gemini-..."` union; update
the line that sets geminiModel in ImageGenSettings.vue to use
ImageGenerationConfigValue so the component stays in sync with backend types.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@src/components/settings/ImageGenSettings.vue`:
- Around line 122-125: Replace the hard-coded literal union cast on the
geminiModel assignment with the backend-derived type: import the
ImageGenerationConfigValue type and cast (or narrow) the event target value to
the appropriate member/union from ImageGenerationConfigValue (e.g., the model
field or an Extract<> of ImageGenerationConfigValue) instead of the inline
`"gemini-..."` union; update the line that sets geminiModel in
ImageGenSettings.vue to use ImageGenerationConfigValue so the component stays in
sync with backend types.

---

ℹ️ Review info

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 64f3bd8 and da9c1dc.

📒 Files selected for processing (3)

• src/components/settings/ImageGenSettings.vue
• src/tools/backend/types.ts
• src/views/HomeView.vue