[NopeCharon]

What this PR does / why we need it:

kctrl package install --dry-run returns before --ytt-overlay-file is processed, so the printed resources silently omit the overlays Secret and the PackageInstall annotation that references it. Piping the output into kapp/ytt therefore produces an installation without the requested overlays.

With this change, when overlay files are supplied (and --ytt-overlays is not set to false), the dry-run:

• prints the same <name>-<namespace>-overlays Secret that a regular install creates (built via the existing YttOverlays.OverlaysSecret()), with namespace set like the other printed resources
• adds the ext.packaging.carvel.dev/ytt-paths-from-secret-name.kctrl-ytt-overlays annotation to the PackageInstall

Like the values Secret in the dry-run output, overlay contents are rendered under stringData so the output stays readable.

Which issue(s) this PR fixes:

Fixes #1389

Does this PR introduce a user-facing change?

`kctrl package install --dry-run` now includes the ytt overlays Secret and the corresponding PackageInstall annotation when `--ytt-overlay-file` is supplied.

Additional Notes for your reviewer:

• Extended TestPackageInstallDryRun (cli e2e) with a section that passes an overlay via --ytt-overlay-file -. The section fails without the fix and passes with it. The dry-run e2e tests do not talk to a cluster, so I ran them locally with KCTRL_E2E_NAMESPACE=kctrl-test.
• Also checked by hand: a single file, a directory of overlays, --ytt-overlays=false (no overlays printed), a missing file (returns an error), and that --dry-run --tty=false | ytt -f - parses the output.

Review Checklist:

• Follows the developer guidelines
• Relevant tests are added or updated
• Relevant docs in this repo added or updated
• Relevant carvel.dev docs added or updated in a separate PR and there's
  a link to that PR
• Code is at least as readable and maintainable as it was before this
  change

Additional documentation e.g., Proposal, usage docs, etc.: