feat(linkedin): add MCP image pipeline to carousel command

Add Step 5.5 (Generate Slide Images) using mcp-image Nano Banana Pro.
Each slide is generated with template-specific styling at 3:4 aspect
ratio. Graceful degradation: if mcp-image unavailable, falls back to
text-only output with manual design guide (existing behavior).

- mcp__mcp-image__generate_image added to allowed-tools
- Template-aware visual styles (5 templates → 5 visual directions)
- Images saved to assets/drafts/carousel-[date]-[slug]/
- Step 6 branches: generated images → publish instructions, no images → design guide
- Removed interactive AskUserQuestion from refinement (friction reduction)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/linkedin-thought-leadership/commands/carousel.md

@@ -117,9 +117,56 @@ Run against the Carousel Quality Checklist from `carousel-templates.md`:
 
 If any item fails, fix before presenting.
 
+## Step 5.5: Generate Slide Images
+
+Generate a visual for each slide using mcp-image (Nano Banana Pro). If mcp-image is unavailable or fails, skip this step — the command degrades gracefully to text-only output with a manual design guide.
+
+1. **Create output directory:**
+   ```bash
+   mkdir -p assets/drafts/carousel-$(date +%Y%m%d)-SLUG
+   ```
+   Replace SLUG with a short kebab-case version of the carousel topic (e.g., `ai-governance`).
+
+2. **Determine consistent style** based on the chosen template:
+   - How-To Guide: Clean numbered layout, light accent color per step, white background
+   - Listicle: Card-style with icon area, soft gradient background
+   - Story / Before-After: Cinematic dark gradient backgrounds
+   - Comparison: Split-screen layout, contrasting color halves
+   - Framework: Diagram-style with connected elements, dark blue background
+
+3. **For each slide (1 through N),** call `mcp__mcp-image__generate_image` with:
+   - **prompt:** `"Professional LinkedIn carousel slide. [TEMPLATE STYLE from above]. Background: [consistent color scheme across all slides]. Bold header text: '[SLIDE HEADER]' in large white sans-serif font near the top. Body text below: '[SLIDE BODY lines]' in smaller matching font. Slide [N] of [TOTAL]. Portrait orientation, clean minimal professional design."`
+   - **aspect_ratio:** `"3:4"` (closest available to LinkedIn's 4:5)
+   - **output_path:** `assets/drafts/carousel-[date]-[slug]/slide-[N].png`
+
+4. **After all slides are generated,** verify the output directory contains the expected number of images:
+   ```bash
+   ls -la assets/drafts/carousel-$(date +%Y%m%d)-SLUG/
+   ```
+
+**On failure:** If any mcp-image call fails, log the error and continue with remaining slides. If ALL calls fail, fall back to the text-only design guide in Step 6.
+
 ## Step 6: Present Complete Deck
 
-Show all slides in order, then the caption, then design guidance:
+Show all slides in order with their text content, then the caption.
+
+**If slide images were generated (Step 5.5 succeeded):**
+
+```
+SLIDE IMAGES
+━━━━━━━━━━━━
+Generated [N] slide images in assets/drafts/carousel-[date]-[slug]/
+
+To publish:
+1. Download the slide images from the folder above
+2. Combine into a single PDF (or upload images directly)
+3. Upload to LinkedIn as a document post
+4. Paste the caption below into the post text
+
+Dimensions: ~896×1200 (3:4) — LinkedIn auto-fits to 4:5 display
+```
+
+**If slide images were NOT generated (Step 5.5 skipped/failed):**
 
 ```
 DESIGN GUIDE
@@ -140,7 +187,8 @@ printf '%s' '<CAROUSEL_CAPTION>' | node ${CLAUDE_PLUGIN_ROOT}/hooks/scripts/clip
 ```
 Then confirm: "Caption copied to clipboard."
 
-Use AskUserQuestion: "Want to refine any slides, or is this ready for design?"
+Offer refinement options as text (no interactive prompt):
+"Want to refine? Options: adjust slide text / change visual style / regenerate specific slide / different hook / ready for publishing."
 
 ## Step 7: State Update