Adds Client.WriteFile (Gitea contents API) so the Gitea client also
implements capture.SummaryWriter. Upserts: a GET resolves the current
blob sha so an existing file is updated (the richer-fidelity-supersedes
rule for re-captured sessions) rather than 422'd. Owner stays the fixed
const; token only in the Authorization header (no leak — regression
tested). Refactors the HTTP path into a shared request() helper so the
contents flow can branch on 404 without it being an error.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
mathiasandClaude Opus 4.8
0e28b2125b