Figure surfaces (Mermaid/SVG/Markdown) in the skill and examples; bundled grill-with-docs

[YuniqueUnic]

Summary

Brings the skill up to date with schemaui 0.16's figure rendering, so agents write forms that show instead of tell — and ships an interview skill so fresh installs can grill without installing anything else.

1. Figure surfaces in SKILL.md

• x-content — a Mermaid diagram, inline SVG, or sanitised Markdown block rendered above a question, for context a sentence can't carry.
• x-options — each enum option (aligned by index) can carry label, description and a figure; the user picks a topology by recognising the picture. radio/select show them; segmented has no room and is rejected.
• x-control: "mermaid" — the answer itself is a diagram, edited in a source editor with a live preview.
• The cheat sheet gains the four new rows; the version note separates the 0.14 control hints from the 0.16 figure surfaces; the hard rules (non-empty source, index-aligned lengths, no figures on "none" options, a figure explains but is never the value) are stated up front.

2. Bundled skills/grill-with-docs

Open-ended designs need an interview before they become a schema. The bundled skill keeps the grill-me discipline — one question at a time, every question with a recommended answer, explore instead of asking, stop when converged — and adds grounding: read the cheat sheet, the examples and the engine's galleries before drafting. The main SKILL.md defers to whatever grilling skill the user already has and only falls back to the bundled one when none exists.

3. Examples and screenshots

• New examples/deployment-architecture.schema.json (中文): three topologies, three rollout strategies and two data layers, each option with its own diagram; a node-level x-content figure on the network section; a figure-free escape hatch on purpose; a mermaid control whose answer is the call graph itself.
• web-research-brief gains the two non-editor surfaces: a process figure above the depth slider and an editable report-flow diagram.
• READMEs embed three new screenshots (control gallery, figure-bearing options, live mermaid editor) and document the new surfaces, the bundled grill skill and the new example.

Test plan

• Every example in examples/ loads clean through schemaui web-snapshot (engine ≥ 0.16)
• Real-browser walkthrough of the new example: option figures, section figure, escape hatch, and the mermaid editor render correctly (screenshots in this PR are taken from it)
• pytest tests/: 21 passed; the 6 pre-existing e2e failures reproduce on main without these changes (environment, not this PR)