fix: match WSL mounted paths case-insensitively during session binding

[Jefferyu]

Summary

• match WSL Windows drive paths case-insensitively when the launcher cwd and Codex session state differ only by case
• share path identity logic across rollout discovery, session binding, process-owned rollout lookup, and workspace-root deduplication
• preserve case-sensitive matching for non-WSL Linux paths and non-Windows-drive WSL paths

Reproduction

On WSL, launch Codex from a Windows-mounted path with one casing while Codex persists the session cwd with another. The HUD fails to resolve the session, leaving only the project name, age, and version visible; F12 navigation contains no session data.

Validation

• corepack pnpm release:check
• corepack pnpm lint
• corepack pnpm typecheck
• corepack pnpm test:coverage (298 passed)
• corepack pnpm build
• manually verified doctor against the affected WSL path-casing mismatch