Devin upstream occasionally encodes transient capacity failures using
Connect code permission_denied with message containing 'high demand'.
CPA's ParseDevinTrailerError currently maps every permission_denied to
HTTP 403. The auth cooldown manager interprets 403 as a 30-minute model
permission cooldown, keeping a recovered model locally unavailable.
This fix narrowly reclassifies the observed high-demand variant as
HTTP 429 (Too Many Requests), so it enters the quota/retry cooldown
path instead of the long permission denial path. Genuine
permission_denied errors (model access denied, plan entitlement denied,
etc.) remain HTTP 403.
Tests: 4 new cases in TestParseDevinTrailerError covering transient
high-demand (429), genuine permission error (403), resource_exhausted
unchanged (429), and case-insensitive matching. All existing tests
pass with no regressions.
d44901f91c