feat(shell): show claude-bridge subscription usage (5h/7d windows) in the bar and /gentle:usage panel #1399

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Problem or opportunity

With Pi on the claude-bridge provider (Claude Code through the Agent SDK, the way a Claude Max/Pro subscription is used from Gentle Shell), the bar shows $0.000 and /gentle:usage (alt+u) reports:

✿ claude-bridge · no subscription usage for this provider

The 5-hour and 7-day plan windows that Claude Code shows with /usage are invisible in Pi, so the user only learns about the window when the bridge returns a five_hour rejection.

The numbers are already delivered to the bridge on every turn. From one morning of bridge log (156 events):

consumeQuery: rate_limit_event {"status":"allowed","rateLimitType":"five_hour","unifiedWindows":{"five_hour":{"utilization":0.63,"resetsAt":1790245200},"seven_day":{"utilization":...}}}

What is missing is the connection:

• Gentle Shell has adapters for openai-codex, anthropic (anthropic-ratelimit-unified-* headers) and nan (feat(shell): show NaN Cloud (nan) per-model usage in the bar and /gentle:usage panel #1177 / feat(shell): show NaN Cloud per-model usage in the bar and /gentle:usage panel #1180), plus the generic gentle-pi:usage-source/v1 hook in lib/shell-usage.ts. Neither pi-claude-bridge nor the @schuettc/pi-claude-bridge fork emits that hook.
• The @schuettc/pi-claude-bridge fork (the build that carries the unreleased upstream fixes, including Opus 5.5 at 1M) already normalizes the SDK events into a process-wide bus: globalThis[Symbol.for("pi.provider-usage.bus.v1")] exposing register / adapters / subscribe / publish, with windows five_hour, seven_day, seven_day_opus, seven_day_sonnet, seven_day_oauth_apps, each carrying usedPercent and resetsAt (src/usage-bus.ts). Gentle Shell does not read it.

Proposed outcome

Show claude-bridge subscription usage in the bar and in /gentle:usage, following the NaN precedent (#1180):

1. When the active model's provider is claude-bridge, resolve globalThis[Symbol.for("pi.provider-usage.bus.v1")]; if present, subscribe and map the latest claude snapshot to ProviderUsage: five_hour and seven_day as the main limits, seven_day_opus / seven_day_sonnet / seven_day_oauth_apps as additional limits, each with used percent and reset time.
2. Render it where Codex shows its percentage in the bar, and as a provider block in the panel.
3. When the bus is absent (upstream pi-claude-bridge without the fork), replace the generic unsupported note with a pending note that says the bridge build does not publish usage, so the user knows why.

I can contribute the implementation once this is approved.

Alternatives considered

• Asking upstream pi-claude-bridge to emit gentle-pi:usage-source/v1: upstream is provider-agnostic and should not learn Gentle Shell's event name; consuming the neutral bus symbol keeps that boundary.
• Reading Claude Code's on-disk usage cache: brittle and undocumented; the SDK already streams the values per turn.
• Leaving $0.000: correct for a subscription but hides that the real budget is the plan window.

Additional context

Windows 11, pi 0.87.1, gentle-pi 3.7.0, gentle-ai 3.7.0, @schuettc/pi-claude-bridge 0.8.0-schuettc.5, Claude Max, model claude-opus-5-5. Originally filed in the wrong repository as Gentleman-Programming/gentle-ai#4945; that one will be closed in favour of this issue. Sibling requests for other providers: #1047, #872, #800, #687, #1261.