feat(baoyu-post-to-wechat): add default color preference and modern theme support

skills/baoyu-post-to-wechat/references/config/first-time-setup.md

@@ -49,14 +49,34 @@ header: "Theme"
 question: "Default theme for article conversion?"
 options:
   - label: "default (Recommended)"
-    description: "Classic layout - centered title with border, white-on-color H2"
+    description: "Classic layout - centered title with border, white-on-color H2 (default: blue)"
   - label: "grace"
-    description: "Elegant - text shadows, rounded cards, refined blockquotes"
+    description: "Elegant - text shadows, rounded cards, refined blockquotes (default: purple)"
   - label: "simple"
-    description: "Minimal modern - asymmetric rounded corners, clean whitespace"
+    description: "Minimal modern - asymmetric rounded corners, clean whitespace (default: green)"
+  - label: "modern"
+    description: "Large rounded corners, pill headings, spacious (default: orange)"
 ```
 
-### Question 2: Default Publishing Method
+### Question 2: Default Color
+
+```yaml
+header: "Color"
+question: "Default color preset? (theme default if not set)"
+options:
+  - label: "Theme default (Recommended)"
+    description: "Use the theme's built-in default color"
+  - label: "blue"
+    description: "#0F4C81 经典蓝"
+  - label: "red"
+    description: "#A93226 中国红"
+  - label: "green"
+    description: "#009874 翡翠绿"
+```
+
+Note: User can choose "Other" to type any preset name (vermilion, yellow, purple, sky, rose, olive, black, gray, pink, orange) or hex value.
+
+### Question 3: Default Publishing Method
 
 ```yaml
 header: "Method"
@@ -68,7 +88,7 @@ options:
     description: "Slow, requires Chrome and login session"
 ```
 
-### Question 3: Default Author
+### Question 4: Default Author
 
 ```yaml
 header: "Author"
@@ -80,7 +100,7 @@ options:
 
 Note: User will likely choose "Other" to type their author name.
 
-### Question 4: Open Comments
+### Question 5: Open Comments
 
 ```yaml
 header: "Comments"
@@ -92,7 +112,7 @@ options:
     description: "Disable comments by default"
 ```
 
-### Question 5: Fans-Only Comments
+### Question 6: Fans-Only Comments
 
 ```yaml
 header: "Fans only"
@@ -104,7 +124,7 @@ options:
     description: "Only followers can comment"
 ```
 
-### Question 6: Save Location
+### Question 7: Save Location
 
 ```yaml
 header: "Save"
@@ -133,7 +153,8 @@ options:
 ## EXTEND.md Template
 
 ```md
-default_theme: [default/grace/simple]
+default_theme: [default/grace/simple/modern]
+default_color: [preset name, hex, or empty for theme default]
 default_publish_method: [api/browser]
 default_author: [author name or empty]
 need_open_comment: [1/0]