Make sub-package verify scripts self-contained with full Apache checks

[skrawcz]

Changes

Updates scripts/verify-sub-packages/verify_*.sh to be fully self-contained release validation scripts. Each one now performs all 6 verification steps autonomously:

1. Downloads artifacts from SVN (or accepts a local artifacts dir)
2. Verifies GPG signatures
3. Verifies SHA512 checksums
4. Runs Apache RAT license check (using repo's .rat-excludes)
5. Builds from source tarball with flit build --no-use-vcs
6. Installs wheel in fresh uv venv and runs functional tests

Also adds scripts/verification-sub-packages.sh orchestrator.

Usage

Reviewer validates a single package:

scripts/verify-sub-packages/verify_sdk.sh 0.9.0 0
scripts/verify-sub-packages/verify_ui.sh 0.0.18 0
scripts/verify-sub-packages/verify_lsp.sh 0.2.0 0
scripts/verify-sub-packages/verify_contrib.sh 0.0.9 0

Or with pre-downloaded artifacts:

scripts/verify-sub-packages/verify_sdk.sh 0.9.0 0 ./path/to/artifacts/

How I tested

Ran all 4 scripts against the dry-run RC0 artifacts built from a fresh checkout:

=== apache-hamilton-sdk 0.9.0-RC0: ALL CHECKS PASSED ===
=== apache-hamilton-ui 0.0.18-RC0: ALL CHECKS PASSED ===
=== apache-hamilton-lsp 0.2.0-RC0: ALL CHECKS PASSED ===
=== apache-hamilton-contrib 0.0.9-RC0: ALL CHECKS PASSED ===