ci(darwin): install ccache's runtime dylib deps (blake3, hiredis, xxhash, zstd)

Symptom (run 25634195866, job 75244019809): the Configure ccache step
on the Darwin llama-cpp build aborted with:

  dyld[5647]: Library not loaded: /opt/homebrew/opt/blake3/lib/libblake3.0.dylib
    Referenced from: /opt/homebrew/Cellar/ccache/4.13.5/bin/ccache
  Abort trap: 6

The previous Darwin fix (acc5588d) addressed missing /opt/homebrew/bin
symlinks after a brew cache restore by force-linking. This is a
different layer: ccache's Cellar dir IS restored from cache and IS
linked, but ccache 4.13 dynamically links against blake3 / hiredis /
xxhash / zstd at runtime, and those dependencies are NOT in the
restored Cellar paths. brew install ccache sees the ccache Cellar
present and skips the install — including skipping installation of
those transitive deps.

Two-part fix:
  - Add /opt/homebrew/Cellar/{blake3,hiredis,xxhash,zstd} to the brew
    cache restore/save paths so future cache-hit runs restore them.
  - Explicitly install + link them in the Dependencies step so even
    a fresh runner (cache miss on a new key) gets them, and brew has
    them on hand for ccache to dlopen.

Caught by run 25634195866. Pre-existing condition on Darwin runners;
surfaced because Darwin builds run more often after the llama-cpp-
darwin consolidation in #9731.

Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>