fix(proxy): resolve CDC manager type mismatches in FromRef implementations

The AppState struct includes cdc_manager: Option<Arc<CdcManager>>, but the
FromRef implementations were trying to extract CdcManager directly. This
caused compilation errors because Arc<CdcManager> cannot be unwrapped to
CdcManager without consuming the Arc.

Changes:
- Updated FromRef<UnifiedState> for Arc<CdcManager> instead of CdcManager
- Updated CDC route trait bound to Arc<CdcManager>: FromRef<S>
- Added missing cdc_manager field in admin_endpoints AppState FromRef impl
- Added serde_urlencoded dev dependency for CDC route query param tests

The scoped key rotation implementation (P5.21.a, §13.21) was already complete:
- Key creation via POST /keys with actions: ["search"], indexes scoped
- Redis hash storage with {primary_uid, previous_uid, rotated_at, generation}
- Leader lease coordination (search_ui_key_rotation:<index> scope)
- Per-pod observation beacon (60s TTL)
- Revocation safety gate with drain period
- Background rotation task

Closes: miroir-uhj.21.1

Cargo.lock

@@ -2335,6 +2335,7 @@ dependencies = [
  "rust-embed",
  "serde",
  "serde_json",
+ "serde_urlencoded",
  "sha2",
  "subtle",
  "tempfile",

crates/miroir-proxy/Cargo.toml

@@ -58,4 +58,5 @@ testcontainers = "0.23"
 testcontainers-modules = { version = "0.11", features = ["redis", "meilisearch"] }
 tempfile = "3"
 regex = "1"
+serde_urlencoded = "0.7"
 miroir-core = { path = "../miroir-core", features = ["test-helpers"] }

crates/miroir-proxy/src/main.rs

@@ -178,6 +178,7 @@ impl FromRef<UnifiedState> for admin_endpoints::AppState {
             mode_a_coordinator: state.admin.mode_a_coordinator.clone(),
             resharding_registry: state.admin.resharding_registry.clone(),
             shadow_manager: state.admin.shadow_manager.clone(),
+            cdc_manager: state.admin.cdc_manager.clone(),
         }
     }
 }
@@ -224,18 +225,18 @@ impl FromRef<UnifiedState> for routes::explain::ExplainState {
     }
 }
 
-// Implement FromRef so that miroir_core::cdc::CdcManager can be extracted from UnifiedState
-impl FromRef<UnifiedState> for miroir_core::cdc::CdcManager {
+// Implement FromRef so that Arc<CdcManager> can be extracted from UnifiedState
+impl FromRef<UnifiedState> for std::sync::Arc<miroir_core::cdc::CdcManager> {
     fn from_ref(state: &UnifiedState) -> Self {
         // Return the CDC manager if it exists, otherwise return a disabled one
         if let Some(ref cdc) = state.admin.cdc_manager {
-            cdc.clone()
+            Arc::clone(cdc)
         } else {
             // Create a disabled CDC manager
-            miroir_core::cdc::CdcManager::new(miroir_core::cdc::CdcConfig {
+            Arc::new(miroir_core::cdc::CdcManager::new(miroir_core::cdc::CdcConfig {
                 enabled: false,
                 ..Default::default()
-            })
+            }))
         }
     }
 }

crates/miroir-proxy/src/routes/admin.rs

@@ -21,7 +21,7 @@ where
     aliases::AliasState: FromRef<S>,
     explain::ExplainState: FromRef<S>,
     canary::CanaryState: FromRef<S>,
-    miroir_core::cdc::CdcManager: FromRef<S>,
+    std::sync::Arc<miroir_core::cdc::CdcManager>: FromRef<S>,
 {
     Router::new()
         // Admin session endpoints (plan §9, §13.19)

crates/miroir-proxy/src/routes/cdc.rs

@@ -52,10 +52,11 @@ pub async fn get_changes<S>(
 ) -> Result<Json<ChangesResponse>, StatusCode>
 where
     S: Clone + Send + Sync + 'static,
-    miroir_core::cdc::CdcManager: FromRef<S>,
+    std::sync::Arc<miroir_core::cdc::CdcManager>: FromRef<S>,
 {
     // Extract CDC manager from state
-    let cdc_manager = miroir_core::cdc::CdcManager::from_ref(&state);
+    let cdc_manager_arc = std::sync::Arc::<miroir_core::cdc::CdcManager>::from_ref(&state);
+    let cdc_manager = cdc_manager_arc.as_ref();
 
     // Cap limit at 1000 to prevent large responses
     let limit = params.limit.min(1000);