Hide unsupported account-usage rows for custom Claude Code endpoint profiles

[Tryanks]

Next-release requirement (2026-09-08): This issue must be completed before the next release. The existing scope, diagnosis and acceptance criteria below remain in force.

Reported behavior

A custom Kimi profile using the Claude Code harness appears in Settings → Usage as “Kimi usage unavailable.” A profile without a supported account-usage API should not appear as a broken usage integration.

Current implementation

The Usage page selects profiles by ProviderKind::Codex | ProviderKind::ClaudeCode. Runtime refresh uses the same broad harness-kind distinction, then passes the profile launch environment into the corresponding native usage probe. The services layer converts probe failures to an error-bearing ProviderUsage.

A harness protocol does not establish that a custom endpoint implements that harness vendor's subscription/rate-limit API. The custom endpoint configuration and authentication mode need to participate in the eligibility decision. Do not special-case the display name “Kimi.”

Requested behavior

• Establish account-usage support for the resolved profile in the owning provider/runtime contract and use it consistently for refresh and presentation.
• Omit unsupported profiles from Usage and avoid repeatedly probing an unsupported endpoint.
• Keep meaningful error/retry states for supported accounts that are signed out, unreachable or temporarily failing. Do not hide all failures or all custom profiles indiscriminately.
• Ensure composer account-limit presentation follows the same support decision, while session token/context usage remains available independently.
• Invalidate stale usage when profile configuration changes.

Acceptance criteria

Cover a custom Claude Code/Kimi endpoint with no usage support, a supported account returning real windows, and a supported account temporarily failing. Renaming a profile must not change eligibility. Verify that unsupported rows disappear without affecting actual session usage or genuine error reporting.

The precise Kimi endpoint/auth configuration still needs to be captured for live reproduction; the overly broad profile filter is confirmed by source inspection.

Code context

Reviewed against main at b4c549787da6 (2026-09-08).

• crates/runtime/src/app/providers.rs
• crates/services/src/provider_usage.rs
• crates/core/src/usage.rs
• crates/ui/src/settings_page.rs