Provision the E2E memory secret into the local vault

`nap gateway vault setup` unwraps the project memory secret once (prompt
on a terminal, or the existing argument/env paths) and stores the
secret, never the passphrase, in memory-secrets.vault.json under the
existing 0600 local vault key. The CLI and MCP workers load it
automatically and MCP never prompts, per
/decisions/local-gateway-no-interactive-unlock and
/decisions/2026-09-29-memory-secret-local-vault. Older versions stay
readable; a rotated active version reports memory_secret_rotated with
the setup next action. `vault forget` revokes local access, including
for running workers. Env passphrases still work, are persisted into the
vault, and are reported as deprecated. Search warns
e2e_index_not_provisioned instead of e2e_index_locked. Local key
creation is 0600 from the start and never replaces a published key.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/test_nap_install_gateway_routes.py

@@ -36,6 +36,11 @@ def run():
 
     assert mod.handle_gateway(["vault", "rotate-secret", "--kind", "memory"]) == 0
     assert calls[-1] == ("gateway", ["vault", "rotate-secret", "--kind", "memory"])
+    # Memory secret provisioning/removal route to the wrapper, which owns the prompt.
+    assert mod.handle_gateway(["vault", "setup"]) == 0
+    assert calls[-1] == ("gateway", ["vault", "setup"])
+    assert mod.handle_gateway(["vault", "forget"]) == 0
+    assert calls[-1] == ("gateway", ["vault", "forget"])
 
     try:
         mod.handle_gateway(["process", "--all"])