Add scaffold smoke tests for generated projects and workflows

[blackopsrepl]

Summary

The CLI is user-facing but current validation still leaves a gap between template correctness and real generated-project behavior.

Problem

Scaffolding is tested in pieces, but representative end-to-end generation flows are not covered strongly enough.

Why This Matters

User-visible regressions in solverforge new and follow-on generation should be caught before release.

Proposed Work

• Add smoke tests for solverforge new.
• Add smoke tests for entity, fact, and constraint generation flows.
• In representative cases, run follow-on cargo check against generated projects.
• Cover both basic and list-oriented flows as they mature.

Acceptance Criteria

• Representative generated projects are exercised in automated tests.
• Regressions in scaffolding behavior are caught before release.

Source

Derived from PR #3 (PRODUCTION_REVIEW_ISSUES_2026-03-20.md).

[blackopsrepl]

Resolved by #25.

The merged PR added ignored scaffold smoke tests for every shipped template and the generate-constraint workflow, then fixed the stale scaffolds and generator output so each generated project cargo-checks cleanly.