ci: Keep Rust enabled when AppImage inputs are absent

[zackees]

Fixes #671. Refs #635 and #670.

Changes

• Evaluate the actual AppImage workflow expression with pinned GitHub @actions/expressions 0.3.61 across 16 typed contexts (four caller events; absent, empty, false and true input values).
• Compare the formatted input with the string false, preserving explicit C-only oracle/test builds while enabling Rust when inputs are absent on ordinary push/PR/tag paths.
• Remove the duplicate workflow_call Rust input declaration introduced when release: Build and validate the Windows ARM64 beta package #664 and ci: Build the release's AppImage with Rust libobs on a manual dispatch too #670 merged. Keep the declared workflow_call Boolean default and explicit daily Rust caller. No production Node dependency is added; the Python test installs the official evaluator in its own temporary directory and cleans it.

RED → GREEN

• 4704be509: test_absent_input_defaults_to_rust has eight failing subcases using the real GitHub evaluator; explicit false and true remain correct.

• a14e19b79: all 16 typed cases pass; 14 focused tests pass, and integration review is clean.

• 39448573b: the duplicate-input regression test fails with two declarations instead of one. The actual PR workflow run 38504479307 also failed before creating any jobs.

• 091753db9: one Boolean input declaration remains; all 15 focused tests pass.

Validation

Fresh ./lint, ./unittest, and all four attestation lanes passed after the duplicate-key correction. The full attestation took 469 seconds and stamped exact pushed head 2d795859cedbd66630350b14b5c3524d9f146e7e (tree 3b38594f9c222e28397575c38921daa3f9c2d8f6). OFF/ON C tests pass with 193 tests in each configuration and 1766 identical exports. The focused tests and integration review are clean.

Actual absent-input PR build 38506716441 succeeded at exact head 2d795859cedbd66630350b14b5c3524d9f146e7e. Its real configure environment reports RUST_LIBOBS: true, and CMake reports OBS-Studio-Rust version: 0.1.0. This proves the expression correction in GitHub Actions rather than only the evaluator test. The same run completed success: all four distribution jobs (Debian, Arch, Fedora, Ubuntu 22.04) pass bundle, first-start, probes and saved-profile scenarios. Debian, Arch and Fedora recordings prove moving screen/camera regions and continuous 440 Hz microphone audio, and the recording verifier rejects frozen/silent/corrupt mutations. Ubuntu 22.04 retains its explicit older test-producer limitation: saved-profile startup passes, but it does not create a recording. All routine PR checks are terminal with no failures; Linux attested lanes legitimately skip. Publication correctly skips in the PR context.

GitHub documents loose equality and null/empty/Boolean coercion in https://docs.github.com/en/actions/reference/workflows-and-actions/expressions; the official evaluator is https://github.com/actions/languageservices/tree/main/expressions.

[zackees]

Additional actual startup RED: AppImage run 38504479307 at the initial #672 head failed before creating any jobs. The merged workflow_call mapping contained two identical rust_libobs keys, added by #664 and #670 in different positions. The workflow structure was invalid; no packaged artifact test ran.

RED 3944857 adds a uniqueness regression that fails with 2 declarations rather than 1. GREEN 091753db9 removes the duplicate and retains the original Boolean type/default true. All 15 focused input/platform tests pass. Review is clean and fresh mandatory gates are running before push. Draft #672 remains blocked from readiness by missing actual packaged AppImage evidence; the zero-job run is not treated as a passing or skipped test.

The macOS stack inherits the schema fix alongside the corrected lipo operand order. No macOS frontend startup success is claimed yet.

[zackees]

Pushed the unchanged stamped head 2d795859cedbd66630350b14b5c3524d9f146e7e. Fresh lint/unit and all four attestation lanes passed (469 seconds); OFF/ON each pass 193 C tests with 1766 identical exports. This adds the genuine duplicate-key RED/GREEN correction to the previously pushed input-expression fix.

The corrected actual PR workflow now creates and executes Build AppImage job 115665794810 in run 38506716441. It remains draft while the actual absent-input build and packaged saved-profile tests finish. The preceding run 38504479307 failed before any jobs and is retained as RED evidence.