Fix simulator cache-memory support and close older issues

[Copilot]

Student runs/successes counters were silently resetting to zero on every run because actions/cache/save executed as a pre-step — before the agent updated profiles.json. Stale [workshop-sim] issues also accumulated with no cleanup.

Changes

workshop-student-simulator.md

• Replaced broken cache pattern — removed actions/cache/restore + actions/cache/save pre-steps; added cache-memory: true to tools:, which persists state after the agent completes
• Updated profile path — all profiles.json references moved from /tmp/gh-aw/agent/sim/data/ to /tmp/gh-aw/cache-memory/ (required by cache-memory)
• Added close-older-issues: true to create-issue safe output — closes previous [workshop-sim] report issues on each new run

tools:
  github:
    mode: gh-proxy
    toolsets: [default]
  cache-memory: true          # replaces cache/restore + cache/save pre-steps
safe-outputs:
  create-issue:
    title-prefix: "[workshop-sim] "
    labels: [workshop, simulation, feedback]
    max: 6
    close-older-issues: true  # closes stale report issues automatically

workshop-student-simulator.lock.yml — recompiled from updated .md (0 errors, 0 warnings)