Anchor the gitignore pattern that silently swallowed the new harness ...

The previous commit added tests/HARNESS-MANIFEST's octavia-pki entry and the script, but git
REFUSED the harness directory and the commit went through without it. Cause: .gitignore
carried `octavia-pki/`, which git matches at ANY depth, so it also matched
`tests/octavia-pki/`.

Consequence had this not been caught: the manifest names a harness that is not tracked, so a
fresh clone runs the gauntlet against a missing directory. repo-lint does not catch it,
because locally the files exist -- only a clone would have shown it.

Anchored to `/octavia-pki/`. Verified three ways rather than assumed: tests/octavia-pki is
now trackable, a root-level workspace copy is STILL ignored so the original protection is
intact, and both per-DC overlays remain ignored.

Same class as F4 earlier today -- a gitignore pattern whose real scope differed from its
intent, in the direction that loses data rather than the direction that leaks it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf