overflow_reason is a v1 field, but it was always null: both overflow
callers passed only trigger="overflow", although each already holds the
error classifier's verdict for the provider rejection it recovers from.
A consumer could not tell a 413 from a context-length rejection or the
Anthropic long-context tier gate.
Both callers now pass the classified reason through _compress_context
into the attempt seed, so the attempt log line and the compaction mark
carry it. The mark keeps it in a closed set (context_overflow,
payload_too_large, long_context_tier, else other) and leaves it null for
every other trigger. The Relay docs list the set instead of calling the
field reserved.
Signed-off-by: mnajafian-nv <mnajafian@nvidia.com>
(cherry picked from commit c3ad6f7fb8bfcc8f9c350f3a4272029d63333c7f)
8810cf24b2