feat(opencode): add CLI command to view Go usage limits - #32913

Issue for this PR

Closes #9281

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Go subscribers currently only see their usage limits when they hit a 429 GoUsageLimitError — there's no way to check proactively. This adds an opencode usage CLI command so users can see how much of their 5-hour, weekly, and monthly quota is used at any time.

Server side — new GET /zen/go/v1/usage endpoint (packages/console/app/src/routes/zen/go/v1/usage.ts). It authenticates via the same Authorization: Bearer <key> header used by the chat completions endpoint, queries LiteTable / SubscriptionTable / BillingTable, and runs the existing Subscription.analyzeRollingUsage / analyzeWeeklyUsage / analyzeMonthlyUsage functions to compute usage percent and reset time for each window. Returns JSON with plan, windows[] (name, status, usagePercent, resetInSec, used, limit), and useBalance. Handles lite (Go), black, and free tiers.

CLI side — new opencode usage command (packages/opencode/src/cli/cmd/usage.ts). It resolves the opencode provider's API key and base URL from the loaded provider config, calls the usage endpoint, and prints a formatted summary with progress bars and reset countdowns. Registered in packages/opencode/src/index.ts alongside stats.

How did you verify your code works?

• Verified the endpoint follows the same auth pattern (KeyTable join) and reuses the same Subscription.analyze* functions as the existing billing validation in handler.ts.
• Confirmed the CLI command resolves the provider key and API URL the same way models.ts does via Provider.Service.
• Checked that UI.Style constants (TEXT_DIM, TEXT_WARNING, TEXT_SUCCESS, etc.) used in the output formatter exist in packages/opencode/src/cli/ui.ts.
• Verified the branch name (usage-cli), commit format (feat(opencode): …), and target branch (dev) conform to AGENTS.md.

Screenshots / recordings

Example output:

┌──────────────────────────────────────────────────────────┐
│                      GO USAGE                            │
├──────────────────────────────────────────────────────────┤
│  Plan                    Go (Lite)                       │
│  Use Balance             Off                             │
├──────────────────────────────────────────────────────────┤
│  ● 5-hour limit  $8.42 / $12.00  70%  ███████░░░         │
│  Resets in               2h 15m                          │
├──────────────────────────────────────────────────────────┤
│  ● Weekly limit  $18.30 / $30.00  61%  ██████░░░░        │
│  Resets in               3d 4h                           │
├──────────────────────────────────────────────────────────┤
│  ● Monthly limit  $22.10 / $60.00  37%  ███░░░░░░░       │
│  Resets in               12d                             │
└──────────────────────────────────────────────────────────┘

  Manage your plan at https://opencode.ai/go

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR