plantuml-migratelisted

# PlantUML Migrate Propagate a Policy change across the project's `.plantuml/` and `.puml` files. The most invasive skill in the plugin — it modifies user files, so safety mechanisms are explicit. ## Flow 1. **Read current Policy** from `CLAUDE.md` § "PlantUML Policy". Abort if absent with `"migrate requires a PlantUML Policy — run /plantuml-init first"`. 2. **Compute expected `.plantuml/`** files as if the Policy were freshly materialized. Run the same generation logic as `plantuml-bootstrap` (see `${CLAUDE_PLUGIN_ROOT}/skills/plantuml-bootstrap/SKILL.md` § "Generation"), but produce in-memory strings instead of disk writes. For each of the four partials (`_brand.puml`, `_theme.puml`, `_fonts.puml`, `_layout.puml`), hold the expected bytes. 3. **Manual-edit detection (hash divergence)** — for each existing `.plantuml/_brand.puml`, `_theme.puml`, `_fonts.puml`, `_layout.puml`: - **Normalize** both sides before hashing to avoid false positives: strip CR (`\r`), collapse trailing whitespace per line, ensure a single trailing newline at EOF. Same normalization on both sides. - Compute SHA-256 via `shasum -a 256` (BSD-compatible across macOS and Linux). - **Idempotency short-circuit**: if all four hashes match expected AND no targets need adding/removing AND no Policy-driven `.puml` edits are needed, print `"migration: nothing to do"` and exit 0. 4. **If any divergence is detected**, list the divergent files and pres