* perf(ci): skip unaffected test jobs
Keep required checks present as skipped jobs and run the full matrix whenever change detection cannot produce a trustworthy result.
* fix(ci): harden change-based job gating
Include shared build inputs in packaged desktop smoke selection and pin the path filter action that controls job execution.
* fix(ci): run CLI checks for Nix packaging changes
The CLI supervision regression suite reads the Nix package definition directly, so include that external dependency in its path filter.
* fix(ci): track external test inputs
Select server and CLI suites when their narrowly scoped cross-package fixtures and source assertions change.
* fix(ci): track server test CLI imports
Run server tests for CLI source changes because the Hub relationship harness executes the CLI command graph directly.
* fix(ci): pin gating checkout action
Keep every third-party action that controls change detection pinned to a verified commit SHA.
