feat(baoyu-image-gen): add OpenRouter provider support

skills/baoyu-image-gen/references/config/first-time-setup.md

@@ -47,6 +47,8 @@ options:
     description: "Gemini multimodal - high quality, reference images, flexible sizes"
   - label: "OpenAI"
     description: "GPT Image - consistent quality, reliable output"
+  - label: "OpenRouter"
+    description: "Router for Gemini/FLUX/OpenAI-compatible image models"
   - label: "DashScope"
     description: "Alibaba Cloud - z-image-turbo, good for Chinese content"
   - label: "Replicate"
@@ -69,6 +71,22 @@ options:
     description: "Fast generation, balanced quality and speed"
 ```
 
+### Question 2b: Default OpenRouter Model
+
+Only show if user selected OpenRouter.
+
+```yaml
+header: "OpenRouter Model"
+question: "Default OpenRouter image generation model?"
+options:
+  - label: "google/gemini-3.1-flash-image-preview (Recommended)"
+    description: "Best general-purpose OpenRouter image model with reference-image workflows"
+  - label: "google/gemini-2.5-flash-image-preview"
+    description: "Fast Gemini preview model on OpenRouter"
+  - label: "black-forest-labs/flux.2-pro"
+    description: "Strong text-to-image quality through OpenRouter"
+```
+
 ### Question 3: Default Quality
 
 ```yaml
@@ -112,6 +130,7 @@ default_image_size: null
 default_model:
   google: [selected google model or null]
   openai: null
+  openrouter: [selected openrouter model or null]
   dashscope: null
   replicate: null
 ---
@@ -147,6 +166,20 @@ options:
     description: "Previous generation GPT Image model"
 ```
 
+### OpenRouter Model Selection
+
+```yaml
+header: "OpenRouter Model"
+question: "Choose a default OpenRouter image generation model?"
+options:
+  - label: "google/gemini-3.1-flash-image-preview (Recommended)"
+    description: "Recommended for image output and reference-image edits"
+  - label: "google/gemini-2.5-flash-image-preview"
+    description: "Fast preview-oriented image generation"
+  - label: "black-forest-labs/flux.2-pro"
+    description: "High-quality text-to-image through OpenRouter"
+```
+
 ### DashScope Model Selection
 
 ```yaml
@@ -183,6 +216,7 @@ After user selects a model:
 default_model:
   google: [value or null]
   openai: [value or null]
+  openrouter: [value or null]
   dashscope: [value or null]
   replicate: [value or null]
 ```

skills/baoyu-image-gen/references/config/preferences-schema.md

@@ -11,17 +11,18 @@ description: EXTEND.md YAML schema for baoyu-image-gen user preferences
 ---
 version: 1
 
-default_provider: null      # google|openai|dashscope|replicate|null (null = auto-detect)
+default_provider: null      # google|openai|openrouter|dashscope|replicate|null (null = auto-detect)
 
 default_quality: null       # normal|2k|null (null = use default: 2k)
 
 default_aspect_ratio: null  # "16:9"|"1:1"|"4:3"|"3:4"|"2.35:1"|null
 
-default_image_size: null    # 1K|2K|4K|null (Google only, overrides quality)
+default_image_size: null    # 1K|2K|4K|null (Google/OpenRouter, overrides quality)
 
 default_model:
   google: null              # e.g., "gemini-3-pro-image-preview", "gemini-3.1-flash-image-preview"
   openai: null              # e.g., "gpt-image-1.5", "gpt-image-1"
+  openrouter: null          # e.g., "google/gemini-3.1-flash-image-preview"
   dashscope: null           # e.g., "z-image-turbo"
   replicate: null           # e.g., "google/nano-banana-pro"
 
@@ -37,6 +38,9 @@ batch:
     openai:
       concurrency: 3
       start_interval_ms: 1100
+    openrouter:
+      concurrency: 3
+      start_interval_ms: 1100
     dashscope:
       concurrency: 3
       start_interval_ms: 1100
@@ -51,9 +55,10 @@ batch:
 | `default_provider` | string\|null | null | Default provider (null = auto-detect) |
 | `default_quality` | string\|null | null | Default quality (null = 2k) |
 | `default_aspect_ratio` | string\|null | null | Default aspect ratio |
-| `default_image_size` | string\|null | null | Google image size (overrides quality) |
+| `default_image_size` | string\|null | null | Google/OpenRouter image size (overrides quality) |
 | `default_model.google` | string\|null | null | Google default model |
 | `default_model.openai` | string\|null | null | OpenAI default model |
+| `default_model.openrouter` | string\|null | null | OpenRouter default model |
 | `default_model.dashscope` | string\|null | null | DashScope default model |
 | `default_model.replicate` | string\|null | null | Replicate default model |
 | `batch.max_workers` | int\|null | 10 | Batch worker cap |
@@ -82,6 +87,7 @@ default_image_size: 2K
 default_model:
   google: "gemini-3-pro-image-preview"
   openai: "gpt-image-1.5"
+  openrouter: "google/gemini-3.1-flash-image-preview"
   dashscope: "z-image-turbo"
   replicate: "google/nano-banana-pro"
 batch:
@@ -90,5 +96,8 @@ batch:
     replicate:
       concurrency: 5
       start_interval_ms: 700
+    openrouter:
+      concurrency: 3
+      start_interval_ms: 1100
 ---
 ```