bench: add zccache store to bench/fastled-examples actions/cache path list #151

Problem

The current bench/fastled-examples workflow caches:

path: |
  ~/.fbuild
  ~/.fastled/global_cache
  fastled/.build/pio/\${{ env.BENCH_BOARD }}

It does not cache zccache's per-TU object store. Iter3 warm run (24626590831) confirmed this is load-bearing: 304 MB restored, per-example compile time unchanged vs cold.

Sub-task of #147. Blocked by #149 (need the canonical path from the setup action).

Fix

Once #149 lands and the setup action outputs zccache-store-path:

- name: \"Phase - restore compile cache\"
  uses: actions/cache/restore@v4
  with:
    path: |
      ~/.fbuild
      ~/.fastled/global_cache
      \${{ steps.fbuild-setup.outputs.zccache-store-path }}  # ← add
      fastled/.build/pio/\${{ env.BENCH_BOARD }}
    key: bench-v3-...  # bump version prefix for a clean iter4

Bump CACHE_BUST in bench.config to force iter4 cold, then empty-commit warm rerun. Expected: warm compile drops meaningfully below cold for the first time on this benchmark.

Related

• [META] fbuild build cache must survive CI tar-extract / cross-runner restore #147 — meta.
• daemon/setup: expose zccache store location so consumer workflows can actions/cache it #149 — setup action must expose the path.
• build: audit zccache per-TU cache keys for cross-runner stability #150 — audit confirms caching zccache actually produces hits cross-runner.
• [META] Fastest possible FastLED examples CI rebuild — profile + benchmark #112 — benchmark consumes this.