Backport of the read-denied and ACTIONS_CACHE_MODE cache-mode gating from
the ESM v6.2.0 line (#2447) to the CommonJS v5 line, released as 5.2.0.
Mirrors the earlier write-denied backport (#2435, 5.1.0).
- Detect the `cache read denied:` prefix on download failures (v2 twirp
path and v1 `_apis/artifactcache` path) and surface it as a core.warning
without failing the run.
- Honor ACTIONS_CACHE_MODE: skip restore when the effective cache-mode does
not permit reads (none, write-only) and skip save when it does not permit
writes (none, read), logging a single non-fatal core.info line. Unset or
unrecognized modes are unchanged.
- Add read-denied and cache-mode tests; bump to 5.2.0 with RELEASES entry.
Copilot-Session: e96deec1-716e-4e14-acdf-a230139420a2
Co-authored-by: Copilot App <[email protected]>
