feat: support Codex fast service-tier aliases

* feat: support Codex fast service-tier aliases

* fix: send Codex fast tier as priority

docs/project-roadmap.md

@@ -41,6 +41,7 @@ All major modularization work is complete. The codebase evolved from monolithic
 
 ### Recent Fixes
 
+- **2026-05-07**: **#760** Codex GPT fast mode is now a first-class CLIProxy model tuning suffix. CCS accepts `gpt-5.4-fast`, `gpt-5.4-high-fast`, and equivalent canonicalized forms in raw env configs, CLI variant creation, and the dashboard model picker; runtime requests now send the base upstream model with `reasoning.effort` plus `service_tier: "priority"` instead of leaking the suffixed alias to CLIProxy upstream routing.
 - **2026-05-07**: **#1103** GitHub Copilot is now treated as a deprecated compatibility bridge. The dashboard moves Copilot out of the active Identity & Access section and into Deprecated, quick setup no longer offers `ghcp` for new onboarding, CLI/help/config copy marks Copilot as deprecated, and existing `ccs copilot` / `ghcp` compatibility paths remain available for current setups.
 - **2026-05-07**: **#1189** Headless settings-profile delegation now preserves native Claude passthrough args without a Claude flag allowlist. Explicit `--channels` values reach Claude Code, future native flags can carry multiple adjacent values, malformed CCS-owned flags no longer swallow the next native flag, and `--prompt=<text>` routes through headless delegation consistently with `--prompt <text>`.
 - **2026-05-03**: **#1172** Local CLIProxy config generation now keeps the CPAMC management dashboard aligned with backend selection. `backend: original` points to the upstream dashboard, `backend: plus` points to the CCS-maintained CPAMC fork, `cliproxy.management_panel_repository` lets advanced users override the panel repository, and stale generated configs are regenerated when the expected panel source changes.