- ui.js: renderUnlock() now emits, per needs_auth free-tier provider, a
  password <input> + Save button + inline status span, all wired to the
  existing saveKey() → /api/set_credential path. Enter also submits.
  Ollama-cloud (no env key — uses its own CLI) still shows the signup
  link only. This is the missing UI I claimed was there in earlier turns
  and wasn't — saveKey() existed as JS but had no DOM element to grab.
- README: full rewrite of "Local UI" section — golden-banner flow
  (signup link + inline paste-and-save), CLI equivalents
  (`external-agents set-credential ENV_NAME [value|-]`), and a
  step-by-step "one-minute walkthrough" transcript that replaces the
  broken docs/screenshot.png reference.
- README: add "How the client finds it" paragraph — `npm i -g` puts
  external-agents-mcp on PATH; `claude mcp add` / `codex mcp add`
  record the literal string; shell PATH resolution does the rest. No
  hosting, no daemon, no registry lookup.

Bumps to 0.2.9.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>