feat(hands-on): add guardrails rules lab and wire into docs

- New hands-on/rules/ interactive page: five toggleable rule sources
  (AGENTS.md, gate-discipline skill, Husky pre-commit, check-ui-contract
  enforcer, commitlint) rebuild a ruled prompt live against a naive prompt.
- Visual system mirrors hands-on/starter (same palette, vanilla JS).
- index.html hands-on section now links both labs.
- docs/operations-guide.md gains a 'Hands-on rules lab' subsection.
- README project structure lists the new lab.
- verify.mjs passes content, interaction, and standalone checks for both labs.

hands-on/rules/README.md

@@ -0,0 +1,28 @@
+# Hands-on · Rules
+
+A tiny, zero-dependency demo showing how rule sources reshape the same prompt.
+
+## Run
+
+Open `index.html` directly. No build, no server, no `npm install`.
+
+## What it shows
+
+- Five rule sources, taken from a real monorepo (`netcracker/interview`):
+  - `AGENTS.md` — repo-wide instruction file.
+  - `.agents/skills/gate-discipline/SKILL.md` — skill body loaded on demand.
+  - `.husky/pre-commit` — git hook that runs other enforcers.
+  - `scripts/check-ui-contract.mjs` — custom CLI enforcer (ratchet).
+  - `commitlint.config.cjs` — commit-msg linter.
+- Each rule has an on/off switch. Toggling a rule prepends its body to the **ruled** prompt.
+- EN ↔ PT toggle keeps both languages useful.
+- "Copy ruled prompt" copies the current ruled-prompt text to clipboard.
+- Responsive on mobile, Full HD, and 4K (one column under 720 px).
+
+## Mirror of `/hands-on/starter`
+
+Same visual system (`--paper`, `--ink`, `--blue`, `--gold`), same vanilla JS pattern, same single-file layout. Drop-in alongside the starter page under `hands-on/rules/`.
+
+## Token budget
+
+Page weight: ~5 KB total, no framework, no fetch.