Both cookie-authenticated HTML form posts (POST / and POST /generate)
now require a CSRF token via gorilla/csrf, the recorded default in
GO_PACKAGE_DEFAULTS.md. The token cookie is independent of the session
cookie, so it also covers the login POST, where no session exists yet
(login CSRF). The token key is derived from the signing key with its own
HKDF salt, so tokens survive restarts and reuse no other key material;
gorilla/csrf supplies crypto/rand generation and constant-time compare.
The form routes sit in a chi group behind the middleware; the hidden
token field is rendered into login.html and generator.html. In local
plaintext HTTP mode (debug) requests are marked plaintext so the library
does not demand an https Referer or set a Secure cookie the browser
would withhold; in production, behind the TLS-terminating proxy, it
enforces its https Referer origin check.
model: claude-opus-4-8
Canonical v2-schema `.golangci.yml`, golangci-lint pins bumped to v2.12.2 in `Dockerfile` and `script/bootstrap`, and the tree brought to `0 issues.` under it.
Three behaviour deltas: `Cache.StoreVariant` takes a context (cancelled requests skip the accounting row, recovered by reconciliation); `MetadataStorage.Store` no longer leaks `.tmp-*.json` on Write/Close/Rename failure (dead-defer bug fix); the `signing_key` too-short error text gained a `value too short:` prefix.
Eviction-loop context cancellation deferred to #102.
Add trailing filename to encrypted URLs for better browser compatibility.
The filename is ignored by the server but helps browsers identify content type.