fix(release): share sibling paths through the workspace (#1)

The release job stopped at the bind-source gate. RUNNER_TEMP is
container-internal on this runner and no runner mount exposes it on the Docker
host, so no sibling container could ever share it; only the workspace is
host-mounted.

Move every path shared between the runner's shell steps and its sibling
containers under $GITHUB_WORKSPACE/.release-work: the release directory, the
release builder's HOME and NuGet cache, both candidate image tars, and the
container SPDX inventory. Resolution now maps the workspace alone to its host
path, and each sibling binds that source at $GITHUB_WORKSPACE and works from
there instead of /source, so a shared path is the same string on both sides of
the boundary. publish-release.sh follows with a single bind and requires the
release directory to sit inside the workspace.

Ignore .release-work in Git so the tag gate's cleanliness check stays true while
artifacts accumulate, and in Docker so artifacts written between the two
candidate builds cannot alter the build context the byte-comparison gate
depends on. Skip it in the dependency inventory as well, keeping the restored
package cache out of the license policy scan.

eng/release_artifacts.py

@@ -30,7 +30,10 @@ def load_json(path: pathlib.Path):
 def dependency_inventory(root: pathlib.Path):
     dependencies = {}
     for lock_path in sorted(root.glob("**/packages.lock.json")):
-        if any(part in {"bin", "obj", "artifacts"} for part in lock_path.parts):
+        if any(
+            part in {"bin", "obj", "artifacts", ".release-work"}
+            for part in lock_path.parts
+        ):
             continue
         lock = load_json(lock_path)
         for framework in lock.get("dependencies", {}).values():