[BUG] install --dry-run falsely previews removal of a required transitive dependency

Describe the bug

After a package with a transitive dependency is installed, rerunning apm install --dry-run from the unchanged consumer manifest omits the transitive package from its dependency preview and incorrectly says the transitive package's deployed files would be removed.

Running the same command without --dry-run resolves both packages and preserves the transitive files.

To Reproduce

1. Create three sibling directories named consumer, parent, and child.

2. Create consumer/apm.yml:

   name: consumer
   version: 1.0.0
   targets:
     - copilot
   dependencies:
     apm:
       - ../parent
   

3. Create parent/apm.yml:

   name: parent
   version: 1.0.0
   dependencies:
     apm:
       - ../child
   

4. Create child/apm.yml:

   name: child
   version: 1.0.0
   

5. Add this instruction at both parent/.apm/instructions/parent.instructions.md and child/.apm/instructions/child.instructions.md:

   ---
   applyTo: "**"
   ---
   # Instruction
   

6. From consumer, run apm install --target copilot. Both packages are installed:

   [+] ../parent (local)
   [+] ../child (local)
   [*] Installed 2 APM dependencies
   

7. Without changing any manifest, run apm install --target copilot --dry-run:

   [i] APM dependencies (1):
   [i]   - ../parent -> install
   [i] Files that would be removed (packages no longer in apm.yml): 1
   [i]   - .github/instructions/child.instructions.md
   

8. Run apm install --target copilot without --dry-run. It resolves both packages and leaves the child instruction unchanged.

Expected behavior

Dry-run reflects the real install plan: it includes the still-required transitive package and does not preview removal of its deployed files.

Environment (please complete the following information):

• OS: macOS
• Python Version: 3.14.7
• APM Version: 0.31.0 installed with Homebrew; also reproduced with current main
• VSCode Version (if relevant): Not applicable

Logs

The relevant output is included in the reproduction above.

Additional context

The dry-run plan collects only the root package's direct and development dependencies and uses those dependencies as its orphan-preview intent. The renderer passes that set to detect_orphans and labels the result as files that would be removed because packages are no longer in apm.yml.

Start by reproducing the three-package scenario with apm install --target copilot followed by apm install --target copilot --dry-run. Read src/apm_cli/install/dry_run_plan.py at the dependency collection and orphan-preview sections, then inspect src/apm_cli/install/presentation/dry_run.py where the result is rendered. Done means dry-run includes the required transitive package and no longer previews its files for removal.