feat: add PDF export for slide-deck and comic skills

skills/baoyu-comic/SKILL.md

@@ -36,6 +36,20 @@ Style × Layout can be freely combined.
 | Wine, food, business, lifestyle, professional | realistic | cinematic |
 | Biography, balanced | classic | mixed |
 
+## Script Directory
+
+**Important**: All scripts are located in the `scripts/` subdirectory of this skill.
+
+**Agent Execution Instructions**:
+1. Determine this SKILL.md file's directory path as `SKILL_DIR`
+2. Script path = `${SKILL_DIR}/scripts/<script-name>.ts`
+3. Replace all `${SKILL_DIR}` in this document with the actual path
+
+**Script Reference**:
+| Script | Purpose |
+|--------|---------|
+| `scripts/merge-to-pdf.ts` | Merge comic pages into PDF |
+
 ## File Structure
 
 ```
@@ -48,7 +62,8 @@ Style × Layout can be freely combined.
 │   ├── 00-cover.md
 │   └── XX-page.md
 ├── 00-cover.png
-└── XX-page.png
+├── XX-page.png
+└── {topic-slug}.pdf
 ```
 
 **Target directory**:
@@ -99,12 +114,13 @@ For each page (cover + pages):
 
 **Image Generation Skill Selection**:
 - Check available image generation skills in the environment
-- Adapt parameters based on skill capabilities:
-  - If supports `--promptfiles`: pass prompt files
-  - If supports reference image: pass `characters/characters.png`
-  - If text-only: concatenate prompts into single text
 - If multiple skills available, ask user preference
 
+**Character Reference Handling**:
+- If skill supports reference image: pass `characters/characters.png` as reference image
+- If skill does NOT support reference image: include `characters/characters.md` content in the prompt
+- This ensures character visual consistency across all pages
+
 **Session Management**:
 If the image generation skill supports `--sessionId`:
 1. Generate a unique session ID at the start (e.g., `comic-{topic-slug}-{timestamp}`)
@@ -113,7 +129,17 @@ If the image generation skill supports `--sessionId`:
 
 3. Report progress after each generation
 
-### Step 5: Completion Report
+### Step 5: Merge to PDF
+
+After all images are generated, merge them into a PDF file:
+
+```bash
+npx -y bun ${SKILL_DIR}/scripts/merge-to-pdf.ts <comic-dir>
+```
+
+This creates `{topic-slug}.pdf` in the comic directory with all pages as full-page images.
+
+### Step 6: Completion Report
 
 ```
 Comic Complete!
@@ -121,6 +147,7 @@ Title: [title] | Style: [style] | Pages: [count]
 Location: [path]
 ✓ characters.png
 ✓ 00-cover.png ... XX-page.png
+✓ {topic-slug}.pdf
 ```
 
 ## Style-Specific Guidelines