test(e2e): drop the two mgmt registry cells no shared-proxy test can cover

mgmt.cache_settings.update.happy_path and
mgmt.config_override.hashicorp_vault.happy_path were the last two uncovered
Management/UI cells, and neither can be covered against the shared proxy the
e2e suites run on. Both routes reconfigure the whole process rather than a
resource the test owns.

/cache/settings persists whatever it receives into a row that outranks the YAML
cache_params and is re-applied on a timer, so a partial write downgrades a TLS
cluster to a plaintext standalone node and every later Redis call hangs. That is
what took out 60 of 72 tests on 2026-07-25 and got the original test removed in
PR #34664.

/config_overrides/hashicorp_vault has the same shape: a POST sets the HCP_VAULT_*
env vars, swaps litellm.secret_manager_client process-wide, and writes a row the
config-reload poll re-applies, so every os.environ/ lookup on the pod resolves
against the test's Vault until the DELETE lands. Its constructor also never
dials Vault, so a POST to a bogus address still returns 200 and a smoke test
built on it would pass for the wrong reason.

Keeping rows we have decided not to cover only inflates the denominator, so drop
them and record the reasoning where someone would go to write the test. Filing
the isolated-proxy harness they both need separately; the cells come back with
it.

Management/UI goes 75/77 to 75/75, headline 402/544 to 402/542.

tests/e2e/coverage_registry/mgmt.yaml

@@ -64,14 +64,12 @@
 - {id: mgmt.budget.list_v1.happy_path, module: mgmt, tier: P1, surface: api, assertions: [happy_path], source: "management_v1/budgets.py:129", rationale: "Budget enumeration the Budgets page can page, sort and filter"}
 - {id: mgmt.budget.list_v1.admin_only, module: mgmt, tier: P1, surface: api, assertions: [admin_only], source: "management_v1/budgets.py:129", rationale: "A caller without admin view is refused, not served an empty page"}
 - {id: mgmt.callback.list.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "callback_management_endpoints.py", rationale: "Callback config (smoke)"}
-- {id: mgmt.cache_settings.update.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "cache_settings_endpoints.py", rationale: "Cache config (smoke). Deliberately uncovered: the previous test read the live settings and wrote them back, which proves nothing (identical values in, so a no-op POST still passes) while being able to break the deployment. /cache/settings persists what it receives and that row outranks YAML cache_params, re-applied on a timer, so a write that omits ssl or redis_startup_nodes turns a TLS cluster into a plaintext standalone node and every later Redis call hangs. That took out 60 of 72 tests on 2026-07-25. GET cannot round-trip it either: it resolves the stored row overlaid with REDIS_* env and never reads YAML, so on a fresh deploy it cannot see YAML ssl to echo back. A safe test needs an isolated proxy, or LIT-4816 fixed so a partial write cannot downgrade transport. Do not re-add a read-then-write-back test against a shared proxy."}
 - {id: mgmt.cost_tracking.estimate.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "cost_tracking_settings.py", rationale: "Cost estimate (smoke)"}
 - {id: mgmt.router_settings.update.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "router_settings_endpoints.py", rationale: "Router config (smoke)"}
 - {id: mgmt.jwt_key_mapping.new.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "jwt_key_mapping_endpoints.py", rationale: "JWT->key mapping (smoke)"}
 - {id: mgmt.compliance.gdpr.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "compliance_endpoints.py", rationale: "GDPR ops (smoke)"}
 - {id: mgmt.tool_management.list.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "tool_management_endpoints.py", rationale: "Tool inventory (smoke)"}
 - {id: mgmt.fallback_management.update.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "fallback_management_endpoints.py", rationale: "Fallback config (smoke)"}
-- {id: mgmt.config_override.hashicorp_vault.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "config_override_endpoints.py", rationale: "Vault integration (smoke)"}
 - {id: mgmt.workflow.list.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "workflow_management_endpoints.py", rationale: "Workflow tracking (smoke)"}
 - {id: mgmt.credential_migration.check.happy_path, module: mgmt, tier: P2, surface: api, assertions: [happy_path], source: "key_management_endpoints.py:4252", rationale: "Encryption migration (smoke)"}
 - {id: mgmt.credential.new.serves_request, module: mgmt, tier: P1, surface: api, assertions: [serves_request], source: "credential_endpoints/endpoints.py:42", rationale: "Stored credential resolves into a deployment and serves a live /messages request"}

tests/e2e/management/test_config_misc_endpoints_e2e.py

@@ -7,9 +7,13 @@ so a read-back reflects the change. Router settings, which mutate global proxy
 state, are exercised with a benign, self-restoring change so a shared proxy is left
 as it was found.
 
-Cache settings are deliberately not covered here; see the rationale on
-mgmt.cache_settings.update.happy_path in coverage_registry/mgmt.yaml before adding
-a test for that route.
+Cache settings and the Vault config override are deliberately not covered here.
+Both routes reconfigure the whole proxy: /cache/settings persists what it receives
+into a row that outranks the YAML cache_params and is re-applied on a timer, and
+/config_overrides/hashicorp_vault swaps the process-wide secret manager. Neither can
+be exercised safely against the shared proxy the suites run on, so they need an
+isolated proxy before a test lands. Do not add a read-then-write-back test for
+either one.
 """
 
 from __future__ import annotations