plantuml-validatelisted

# PlantUML Validate Render-aware validation across `.puml` × declared targets, with three levels of stringency. ## Args - `mode=check` (default) — compare current render against baseline. - `mode=bless` — capture current render as new baseline. - `level=checkonly` (default) — `plantuml -checkonly`, deterministic cross-machine, no image output. - `level=svg-hash` — render SVG, normalize, hash. Stable cross-machine if fonts are pinned. - `level=png-perceptual` — opt-in, fragile across systems. Not implemented in v1.0.0; the renderer agent returns `unsupported`. ## Flow 1. **Read Policy** from `CLAUDE.md` § "PlantUML Policy". Extract Primary + Additional targets. Abort with a clear message if Policy missing. 2. **Enumerate** `.puml` files (excluding `.plantuml/_*.puml`). 3. **Compute matrix** `file × target`. 4. **Compute baseline path** for each cell: `tests/plantuml-baselines/<flat-relpath>--<target>.<level>` where `<flat-relpath>` is the file path relative to the project root with `/` replaced by `__` and the `.puml` extension dropped (e.g. `diagrams/auth/Foo.puml` → `diagrams__auth__Foo`). This avoids silent collisions when two diagrams share a stem in different directories. 5. **For `mode=check`**: if any baseline is missing, abort and tell the user `"no baselines found, run with mode=bless to capture current state"`. (If only some are missing, list them; do not silently skip.) 6. **Dispatch** each cell to `puml-renderer` via `Task` in par