Validate extension settings and test released and main ActivitySim/Sharrow

[jpn--]

Enable resident extension settings validation and move the example to released ActivitySim 1.6.0 and Sharrow 2.16.2, with CI coverage for both the locked releases and the current main branches of both dependencies.

Changes

• Register extension settings with the preflight checker, including external worker identification and the corrected external non-mandatory model name. Enable preflight for resident runs.
• Add tests for all three resident settings variants, active extension coverage, invalid schemas, missing specification/coefficient files, invalid AV ownership logit types, and inactive extensions.
• Replace the ActivitySim Git source override with release dependencies and refresh the project and standalone script lockfiles. Remove the standalone scripts' outdated package cutoff.
• Run the full suite in independent release and upstream-main CI jobs, reporting the installed dependency versions.

Existing regression targets and model specifications are unchanged.

Validation

• All 34 tests passed locally on Python 3.11/macOS with ActivitySim 1.6.0 and Sharrow 2.16.2, including Sharrow and non-Sharrow regression runs. The final project lockfile selects the same dependency packages as that tested environment.
• All 32 settings-checker tests passed again after applying the dependency updates.
• Validated all three standalone script lockfiles with locked dry-run syncs; full-scale standalone simulations were not run.
• Validated the CI matrix structure and checked the diff for whitespace errors.
• GitHub CI for the latest commit is still in progress: https://github.com/driftlesslabs/sandag-abm3-example/actions/runs/35485360103