fix(desktop): discover current Cursor Agent CLI

[p-prash]

Summary

• Update the Cursor preset to launch the current Cursor Agent CLI as agent acp.
• Preserve cursor-agent as a resolution alias for persisted records and older custom configurations, including Windows .exe, .cmd, and .bat forms.
• Update harness UI test fixtures and add Rust regression coverage pinning the canonical preset and legacy alias.

Validation

• just desktop-tauri-test — 3,174 passed, 0 failed (19 ignored); all additional test binaries passed.
• cargo fmt --manifest-path desktop/src-tauri/Cargo.toml --all -- --check
• pnpm --dir desktop exec biome check tests/e2e/harness-catalog-screenshots.spec.ts tests/e2e/harness-management.spec.ts
• pnpm --dir desktop exec tsc --noEmit
• pnpm --dir desktop run test:e2e:smoke -- tests/e2e/harness-catalog-screenshots.spec.ts tests/e2e/harness-management.spec.ts — 16 passed

Closes #739

[github-actions]

🔐 Codex Security Review

Status: review required for the current range.

The current range is 092c6a7277698bd373ccbc1d008fc1507094ae74...7324acbe17ced52281a3bae0cedc469aa1b3ce33.
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[p-prash]

Closing: this change targeted the wrong repository. The relevant work belongs in the Impel Hub codebase; apologies for the noise.