[Bot] docs: release notes for v0.5.0

docs/release-notes/v0.4.md

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+<a id='changelog-v0.5.0'></a>
+## v0.5.0 — released 2026-08-19
+
+### Action required
+
+Neutron no longer falls back to querying Ironic for a baremetal port's
+`physical_network` when it is absent from the port's `binding_profile`. It is
+now a hard requirement: without it, binding a baremetal port is refused and
+trunk create and delete operations are rejected with a `BadRequest`.
+
+Before upgrading, confirm no bound baremetal ports are missing
+`physical_network`, and backfill any that are:
+
+1. Take a report-only inventory of affected ports in each cloud:
+
+    ```bash
+    ./scripts/audit_ports_missing_physical_network.py --os-cloud $CLOUD
+    ```
+
+2. If the report lists any ports, backfill them from their Ironic baremetal
+   port:
+
+    ```bash
+    ./scripts/audit_ports_missing_physical_network.py --os-cloud $CLOUD --execute
+    ```
+
+3. Re-run step 1 and confirm it reports no matches.
+
+A port whose trunk parent is still bound but has no `physical_network` cannot
+have its trunk deleted until the profile is corrected. Trunks whose parent port
+is unbound are unaffected and delete as before.
+
 ## v0.4.25 and earlier
 
 Per-version upgrade notes begin with **v0.4.26**. For earlier versions the only