fix(snippets): satisfy the parity guards the drift check tripped

Two CI failures, both the guards working as intended rather than defects
in them:

- The MCP tool-name manifest and the REST route/service parity lists are
  explicit, so a new capability has to be added to both surfaces or the
  test fails. verify_snippet / verify_snippet_route / record_verification
  added, plus an assertion that the `verification` filter reaches both
  callers — a verdict an agent records must be visible to the human
  looking at the same corpus, or the two surfaces disagree about what's
  rotten (rule #33).

- vue-tsc rejected two object-literal lookups keyed by the status union:
  `status` includes "ok" and "unverified", and an object literal has to
  enumerate every member even just to say "nothing to show for these".
  Typed as Record<string, string>, which is what the ?? "" fallback
  already assumed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UaYUaouG9jjhATyuxCKrQs

tests/test_mcp_tool_snippets.py

@@ -228,5 +228,5 @@ def test_register_attaches_all_tools():
     snippets.register(FakeMcp())
     assert set(names) == {
         "list_snippets", "create_snippet", "get_snippet", "update_snippet",
-        "delete_snippet", "merge_snippets",
+        "delete_snippet", "merge_snippets", "verify_snippet",
     }