ci: comprehensive docs-orchestrator audit and fixes

- Add safe.directory + fetch-depth: 0 for container jobs
- Support workflow_dispatch in metadata-regen and deploy-aws
- Guard PR comments against fork PRs
- Add ccache save to pr-metadata-regen
- Use metadata_sync.sh --generate --sync instead of manual steps
- Fix msg_docs source path in metadata_sync.sh
- Guard set-version against non-release branches
- Clean up build-site needs list

Signed-off-by: Ramon Roche <mrpollo@gmail.com>

Tools/ci/metadata_sync.sh

@@ -233,7 +233,7 @@ sync_modules() {
 }
 
 sync_msg_docs() {
-    local src_dir="build/px4_sitl_default/msg_docs"
+    local src_dir="build/msg_docs"
     local dest_dir="docs/en/msg_docs"
     local middleware_dir="docs/en/middleware"