v1.12.3

A patch release over 1.12.2. Whitespace around the controller's bearer token and the skills curator's API key no longer
matters, and one security fix: an API_BEARER_TOKEN made only of whitespace worked as a credential. Update the
controller (its image, or your source checkout) to get the fixes. The client, LangChain and MCP bridge packages change
too: they strip the token they send. If your token has spaces or tabs around it, update the controller before the
clients (Upgrade notes).

Upgrade notes

• The 32-character floor for API_BEARER_TOKEN (production, or reachable off the box) now measures the token without
  its surrounding whitespace. A token that cleared it only because of padding is refused at startup; replace it with a
  longer one.
• If your API_BEARER_TOKEN has spaces or tabs around it, update the controller before the clients. The new clients
  send the token stripped, which an older controller compares with the padded value and refuses; the new controller
  accepts both.

Security

• An API_BEARER_TOKEN made only of whitespace is no longer a credential (#252). It was compared like any other
  token, so Bearer followed by the same whitespace authenticated under uvicorn's default HTTP parser, and a run of 32
  or more spaces even cleared the production length floor at startup. It now counts as unset, as an empty
  API_BEARER_TOKEN= already did. Without named API_BEARER_TOKENS, a controller reachable off the box or running with
  APP_ENV=production refuses to start ("API_BEARER_TOKEN is required"), and one on loopback otherwise runs as the
  documented no-token default and logs the existing warning. Exploiting it needed an operator to have set such a token;
  nothing ships one.

Fixed

• Whitespace around the bearer token no longer matters (#252). The controller compared the whole Authorization
  header with Bearer <API_BEARER_TOKEN>, byte for byte, so a token pasted with a space or newline around it matched
  only a client that sent the same whitespace, and a trailing newline (common in secret files) matched nothing the HTTP
  parser would pass through. The controller now strips API_BEARER_TOKEN and WITNESS_REMOTE_API_KEY (named
  API_BEARER_TOKENS were already stripped), and ignores spaces and tabs around the token in the header it receives
  (Bearer must still be followed by a space), so curl, the repo's shell helpers and third-party MCP clients that send
  a padded token still match. The rate limiter keys on the same normalized header, so every spelling of one token shares
  its bucket. The first-party senders strip the token before sending: the MCP stdio bridge (--bearer-token,
  AUTO_BROWSER_BEARER_TOKEN), the Python SDK client, the LangChain AutoBrowserTool and AutoBrowserNode, the eval
  client behind scripts/agent_eval.py, and the dashboard. A client given a whitespace-only token sends no
  Authorization header. Padding the HTTP library refused (a newline after the bridge's token, a space before the
  witness key) used to put the whole value in the bridge's error reply and in the controller's witness-delivery warning;
  it is stripped before sending now.
• The skills curator's API key is stripped too (#251). 1.12.2 strips whitespace around the eight provider keys in
  the controller's settings, but the curator (CURATOR_ENABLED) reads ANTHROPIC_API_KEY, OPENAI_API_KEY or
  GEMINI_API_KEY from the environment itself, so a key with a space or newline around it still went out as-is and the
  provider refused it. The curator now strips it as well, and a key that is only whitespace counts as unset.