nebula-mesh: Newly-minted operator API key exposed in redirect URL (Referer, history, proxy logs)

internal/web/operators.go:251 — after handleOperatorCreateAPIKey mints a fresh 32-byte bearer token, the redirect points the operator's browser at:

/ui/operators/<id>?new_key=<raw-token>&key_name=<name>

The raw API key ends up:

• in the browser's URL history
• in the Referer header on every cross-origin asset the detail page loads (any third-party SVG/CSS/JS resource the layout pulls in)
• in any reverse-proxy or load-balancer access log on the path (nginx default combined log captures the query string)
• in any structured log sink the operator's local browser-history backup tool ships out

Authorization: Bearer <token> headers go through the same hops without these problems because access logs typically don't capture request headers and the browser doesn't replay headers cross-origin.

Same handler also appends name (r.FormValue("name")) to the query string without url.QueryEscape, so an & in the operator-supplied key name corrupts query parsing and a \r\n in older proxies could split response headers.

Affected

All released versions up to v0.3.1.

Reproducer

As admin, create an API key via /ui/operators/<id>/api-keys (form POST). The 303 Location header carries the raw token in the query string. Open browser DevTools → Network → response headers; or check the reverse-proxy access log; or check the operator-detail page's Referer-emitting fetches.

Suggested fix

Stash the raw key in a one-shot server-side flash storage (e.g., a row in operator_sessions keyed by session token, with a one_shot_token column and consumed_at) or in a short-lived signed cookie. Render the key once inline on the detail page after the redirect, and clear the storage on render. Pattern mirrors the recovery-codes display in the TOTP flow.

If the flash-storage refactor is too invasive, the minimal fix is to render the key inline via a POST → 200 OK with HTML (no redirect), losing the post-redirect-get idiom but eliminating the URL exposure.