Support CLIProxyAPI-Rust in the Model Usage widget

[DigitalPals]

The Model Usage widget previously queried Go-only management endpoints, so CLIProxyAPI-Rust returned a misleading management-key error. Vendor Model Usage 1.2.0 to detect both implementations automatically and show native Rust Claude/Codex quota windows and last-completed-request activity using the existing connection settings.

Rust readings preserve server observation times and mark stale or unavailable quota data honestly. Credits stay unknown and banked-reset actions are disabled because Rust does not expose those capabilities. Existing Go support remains covered by the upstream regression suite. Native nanosecond timestamps are normalized to microseconds for Python 3.10 compatibility.

Share Quickshell payload preparation between checkout and RPM packaging, with byte-for-byte Model Usage parity coverage. The pinned upstream commit bc771a070ba1a18a3566a7006ecd1ba8c000713c is published on DigitalPals/omarchy-modelusage main.

Validation:

• Upstream CI passed on Python 3.10, 3.11, 3.12, 3.13, and 3.14: https://github.com/DigitalPals/omarchy-modelusage/actions/runs/37113912949
• python3 -B tests/model-usage.py: passed; final upstream suite has 159 Python tests plus JavaScript assertions.
• ./tests/run: all 17 stages passed for the final correction; separate real-engine lifecycle smoke skipped with the managed shell active.
• python3 -B image/check-source: source and payload parity checks passed for the final correction.
• Development RPM installed live through DNF: both provider panels rendered, six accounts and nine quota windows detected, native activity matched account identities, and the existing key/settings were preserved.
• Sole managed Quickshell instance and clean current-invocation journal verified; installed RPM verification reported no drift.

The live development RPM uses the initial adapter commit d34db47 on Python 3.14, which already supports Rust nanosecond timestamps. This is not a full ISO installation qualification. Research, API limitations, and the verification record are in docs/cliproxy-rust-model-usage-research.md.