add-providerlisted

# Adding a provider to Toki Toki knows two kinds of provider: - **Agent-only** (Copilot, Grok, Gemini, Cursor): no usage/quota API. A running CLI is detected by scanning processes and shows as a row in the Agents tab. To also get a standing card on the main page (reading "No usage API available"), the provider needs either auto-detection when its CLI is installed (like Cursor) or a configured/connected account (like Grok/Gemini). A provider with neither (Copilot) only appears as an Agents row while a session runs. Most new providers are this kind, so start here. - **Usage-API** (Claude Code, Codex, OpenCode, Pi): has a readable data source, a quota/credential API (Claude Code, Codex) or local session history (OpenCode, Pi), so it gets a dedicated client and a real percentage/spend card. The fastest reference is the **Cursor** implementation. Read commits `6345d66` (detection), `1743942` (auto-detected card), and `59be714` (logo, widget glyph, widget test); together they are the template for an agent-only provider. ## Step 0a: get the logo Ask the user for the provider's logo as a **local SVG file path or a URL** before writing UI code. Then: - If a URL, download it. Prefer a clean single-color or flat SVG that reads at 16-22px. - Save it as `Sources/Toki/Resources/<provider>-logo.svg`. `scripts/build-app.sh` copies `*-logo.svg` into the widget bundle automatically, so one file covers app and widget. - If the user has no logo, fall back to an SF Symbol (like `.copilot` d