Add plugin entry: tokenmaxx

[pedroapfilho]

What the plugin does

Adds a nav panel for tokenmaxx, the local proxy that keeps
several Codex and Claude Code subscription accounts signed in and picks which one serves each
request.

• Accounts one card per provider, accounts ordered by headroom, a bar per rate-limit window with
  reset countdowns, make-active, sign out, Codex reset credits, hide a window, and auto-rotation with
  threshold, hold, and hysteresis.
• Analytics token throughput and cost at API list prices from 1 hour to 31 days, with
  per-provider and per-model breakdowns.
• Setup daemon start and stop, proxy address, OAuth or API-key sign-in, routing install and
  uninstall for codex, claude, and pi, and the full tokenmaxx doctor report.

The sidebar row carries the fullest window across the active accounts, so pressure is readable
without opening the panel.

Source release

git source, https://github.com/pedroapfilho/bb-plugin-tokenmaxx.git, range ^0.1.1, tagged
v0.1.1 (annotated, never moved). v0.1.0 is also tagged.

Plugin checks

• npx tsc --noEmit clean for both entries.
• bb plugin build emits dist/server.js, dist/app.js, and dist/app.css.
• Clean clone with npm install --omit=dev under NODE_ENV=production builds both artifacts, so the
  git install path works without dev dependencies.
• Installed and exercised against a live tokenmaxx 0.0.65 daemon: state, usage refresh, doctor,
  policy updates, hidden windows, reset-credit read, account switch, and the login terminal stream.

Marketplace checks

• npm ci --ignore-scripts, npm run build, and npm run check all pass (63 entries).
• Icon vendored at icons/tokenmaxx-05b77465.svg (original artwork, 2 paths, no scripts or remote
  references), filename hashed from its content.
• author.github is the account opening this pull request.

Security and permissions

• Talks to tokenmaxx's local unix socket at ~/.tokenmaxx/runtime/manager.sock for reads and
  account actions, and shells out to the tokenmaxx binary only for doctor, routing install and
  uninstall, daemon control, and login.
• Login runs tokenmaxx login <provider> in a bb terminal because the provider CLIs need a pty. The
  plugin never reads or stores credentials: tokenmaxx puts them in the macOS Keychain, and an API key
  is typed into that terminal rather than passed on a command line.
• No network calls of its own, no telemetry, no data leaves the machine.
• macOS only, since tokenmaxx is macOS only.