feat: add /usage usage tracking (codex/copilot/claude)

[CasualDeveloper]

Problem

No way to view remaining plan usage/limits for authenticated providers (Codex, Copilot, Claude) inside the TUI.

Current State

• /usage API is the single source of truth (UsageRoutes factory), endpoint-only fetching (not via header parsing).
• /usage command opens a dialog and fetches latest data; sidebar shows usage and refreshes after assistant turns.
• /usage always fetches latest data for either current provider or all providers; pass --current and --all to override config of fetch scope.
• Config: tui.show_usage_scope defaults to current and controls sidebar + /usage default scope.
• Sidebar refreshes on usage.updated events from the server.
• Fetchers return { snapshot, error } and surface status details in the dialog.
• Copilot usage auth: opencode auth login prompts for a second device flow (VS Code client id) and stores usage token in auth.json; copilot_internal/user uses that token.
• SDK/OpenAPI regenerated.

Open Threads

• Decide Claude 401 handling (reauth hint vs refresh flow).
• Decide whether to surface provider errors when another provider succeeds.
• Re-run bun turbo typecheck and bun run --cwd packages/opencode test test/server/usage.test.ts after latest UI/config changes.

Acceptance Criteria

• GET /usage returns entries only for authenticated providers (codex/copilot/claude)
• /usage dialog renders all returned windows (Codex: hourly/weekly; Claude: 5h/7d/Opus 7d; Copilot: quota + reset date)
• Sidebar renders the same data (SSoT via /usage) and refreshes after assistant turn completion
• Config tui.show_usage_scope controls default scope; /usage --current|--all overrides
• Typecheck + tests pass

Related

• Closes Github Copilot: Tracking Premium Requests #768
• Supersedes feat: display Anthropic and OpenAI OAuth usage in status dialog and sidebar #6905
• Supersedes feat: add usage tracking API and /usage dialog #7837

AI Assistance

• OpenCode + openai/gpt-5.2-codex; human reviewed.

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Github Copilot: Tracking Premium Requests #768: Github Copilot: Tracking Premium Requests - requests tracking for Copilot provider usage quota

Feel free to ignore if none of these address your specific case.

[CasualDeveloper]

Thanks for the pointer. Related to #768 for Copilot quota visibility, but this issue is broader: adds a unified /usage API + TUI surfaces for codex/copilot/claude (including 5h/7d/Opus 7d windows) and is not limited to Copilot premium requests. I'll keep #768 referenced here.

AI Assistance: OpenCode + openai/gpt-5.2-codex; human reviewed.

[improdead]

Hey made an pr about this with images check it out :)
so copilot we need a separate authentication flow since uage data is is not accessible through the one in auth.json and also added antigravity for the plugin Antigravity + Gemini CLI OAuth Plugin for Opencode due to large popularity