Construction Project Timeline Visualizer

### Prompt – Construction Project Timeline Visualizer
**Context**
- **Project name**: {{project_name}}
- **Milestones** (list each as `Phase | Start Date | End Date`):
  {{milestones}}
- **Phase colors** (optional, format `Phase: #hex`):
  {{phase_colors}}
- **Desired output size** (e.g., A4, 1920x1080): {{size}}

**Task**
1. Act as a senior construction planner and convert the milestone list into a structured Gantt‑chart description.
2. Generate a **Midjourney prompt** that will render the timeline image with:
   - Horizontal bars for each phase, colored per `phase_colors` (default palette if omitted).
   - Date labels on the X‑axis.
   - Clear legend linking colors to phases.
   - Professional typography (sans‑serif) and minimal background.
3. Output the following in **Markdown**:
   - `## Timeline Spec`
   - `### Milestone Table` (markdown table of input data)
   - `### Midjourney Prompt`
   - `### Rendering Instructions` (aspect ratio, `--v 6`, `--ar` for size)

**Quality Bar**
- All dates must be ISO‑8601 (YYYY‑MM‑DD).
- Bars must be proportionally sized to duration.
- Prompt length ≤ 80 tokens.
- The final image must be legible when printed at the requested size.

**Constraints**
- Do not fabricate phases or dates.
- Keep the visual style corporate‑clean; no decorative icons.
- Return ONLY the markdown content.