fix(rename): second review pass on the package rename

- The post-task reclaim skip recognises the legacy application.* embed name,
  so query embeds queued by the previous release do not pay a full collect.
- The Azure compose file mounts host data on /app/{indexes,inputs,vectors},
  where the process actually reads and writes; it mounted /app/application/...
  before the rename and /app/docsgpt/... after it, and nothing wrote to either.
- The offline image check triggers on docsgpt/requirements*.txt again;
  dependabot's pip entry points at docsgpt/.
- install_hint() and its docstring name docsgpt/requirements-<extra>.txt;
  the test asserts the full path.
- application/vectors/ stays ignored: the compose files still mount it.
- The durability QA script quiets the docsgpt logger tree.
- Upgrade note: the three renamed source-sync entries start their timers
  from the upgrade.

tests/test_celery.py

@@ -250,6 +250,10 @@ class TestReclaimIsSkippedForEmbeds:
     def test_the_embed_task_is_skipped(self):
         assert not self._collects("docsgpt.vectorstore.embeddings_tasks.embed_texts")
 
+    def test_the_legacy_embed_name_is_skipped_too(self):
+        """Messages from the previous release carry the application.* name."""
+        assert not self._collects("application.vectorstore.embeddings_tasks.embed_texts")
+
     def test_parsing_still_reclaims(self):
         assert self._collects("docsgpt.api.user.tasks.parse_document")