cowork: fix terraform rollback generator correctness and safety

[Coding-Dev-Tools]

Fixes two correctness/safety issues in rollback.py Terraform rollback generation:

1. Empty plans: previously produced a header plus a blanket terraform destroy -auto-approve && terraform apply -auto-approve suggestion even when there was nothing to roll back. Now short-circuits to a single # No changes to roll back line.
2. Contradictory commands for replacements: resources with create_before_delete/delete_before_create/replace actions appeared in both the creates list (destroy) and the destructive list (apply), emitting destroy-then-apply for the same resource. Replacements now revert via a single apply of the previous config; pure creates get destroy, pure deletes get an explicit restore comment.

Adds tests/test_rollback_safety.py regression tests and updates the empty-plan edge-case test. 125/125 tests green, ruff clean.

[github-actions]

🤖 Automated Code Review

✅ Ruff Lint — No issues

⚠️ Ruff Format — Formatting needed

unformatted: File would be reformatted
   --> src/deploydiff/cli.py:76:15
    |
75  | )
76  + @click.option("-v", "--verbose", is_flag=True, help="Show before/after details for each change")
77  | @click.option(
    -     "-v", "--verbose", is_flag=True, help="Show before/after details for each change"
    - )
    - @click.option(
78  |     "--exit-on-destroy",
79  |     is_flag=True,
80  |     help="Exit with code 1 if the plan contains destructive changes (deletes or replaces)",
81  | )
    - def preview(
    -     terraform_file, cloudformation_file, pulumi_file, verbose, exit_on_destroy
    - ) -> None:
82  + def preview(terraform_file, cloudformation_file, pulumi_file, verbose, exit_on_destroy) -> None:
83  |     """Preview infrastructure changes from a plan file."""
--------------------------------------------------------------------------------
129 | )
    - def cost(
    -     terraform_file, cloudformation_file, pulumi_file, pricing_file, threshold
    - ) -> None:
130 + def cost(terraform_file, cloudformation_file, pulumi_file, pricing_file, threshold) -> None:
131 |     """Estimate monthly cost impact of infrastructure changes. (Pro feature)"""
--------------------------------------------------------------------------------
199 |     if len(provided) > 1:
    -         console.print(
    -             "[red]Error: Provide only one source file (--tf, --cfn, or --pulumi)[/red]"
    -         )

✅ Secret Detection — Clean

✅ Large Files — Within limits

📊 Diff Stats — 3 file(s) changed

 src/deploydiff/rollback.py    | 43 ++++++++++++++++++++++++++++++-------
 tests/test_edge_cases.py      |  5 +++--
 tests/test_rollback_safety.py | 50 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+), 10 deletions(-)

---

Verdict: ⚠️ Warnings — Lint/format issues found. Recommend fixing before merge.

Automated by Coding-Dev-Tools/.github reusable workflow.