feat(system-builder): CALL A REST in TRY IT, and ON THE SAMPLE (4f6c)

[over2take]

Approved mockup docs/mockups/builder-rests.html (2026-10-09), decisions 7 and the RESTS page's sample box. Completes 4f.

• TRY IT: A REST, under HEALTH. One of the draft's rests on the made-up character and its pretend token, dice rolled (POST /try-rest, roll: true); the line the game would log goes in the health log, and the health views are asked for again so the model's panel and what others see follow the rest.
• RESTS: ON THE SAMPLE. The picked rest on the sample character, its token hurt to half so "to full" shows, worked out by the server a moment after each edit with dice left to roll; an off rest says to turn it on.
• sheets/tryIt.ts: afterRest (refilled numbers back into the character, the health model's own fields into the health sheet, formulas left to the server) and hurtToken. systemsApi.tryRest and TriedRest.

Summary

Test plan

• Tested locally
• Tests pass

Pre-merge checklist

Code quality:

• Code follows project style
• No breaking changes (or clearly documented)
• No console errors or warnings

Version & Release:

• Version bumped? If releasing to users, update:
  • frontend/package.json version
  • docker-compose.yml APP_VERSION
  • CHANGELOG.md with release notes
• GitHub Actions will auto-tag Docker images with the new version

Before merging to main:

• All tests passing
• PR reviewed and approved
• Branch is up to date with main
• No merge conflicts

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