endpoint_storage compute_ctl integration (#11550)

Add `/lfc/(prewarm|offload)` routes to `compute_ctl` which interact with
endpoint storage.

Add `prewarm_lfc_on_startup` spec option which, if enabled, downloads
LFC prewarm data on compute startup.

Resolves: https://github.com/neondatabase/cloud/issues/26343

libs/compute_api/src/responses.rs

@@ -46,6 +46,30 @@ pub struct ExtensionInstallResponse {
     pub version: ExtVersion,
 }
 
+#[derive(Serialize, Default, Debug, Clone)]
+#[serde(tag = "status", rename_all = "snake_case")]
+pub enum LfcPrewarmState {
+    #[default]
+    NotPrewarmed,
+    Prewarming,
+    Completed,
+    Failed {
+        error: String,
+    },
+}
+
+#[derive(Serialize, Default, Debug, Clone)]
+#[serde(tag = "status", rename_all = "snake_case")]
+pub enum LfcOffloadState {
+    #[default]
+    NotOffloaded,
+    Offloading,
+    Completed,
+    Failed {
+        error: String,
+    },
+}
+
 /// Response of the /status API
 #[derive(Serialize, Debug, Deserialize)]
 #[serde(rename_all = "snake_case")]

libs/compute_api/src/spec.rs

@@ -172,6 +172,15 @@ pub struct ComputeSpec {
     /// Hostname and the port of the otel collector. Leave empty to disable Postgres logs forwarding.
     /// Example: config-shy-breeze-123-collector-monitoring.neon-telemetry.svc.cluster.local:10514
     pub logs_export_host: Option<String>,
+
+    /// Address of endpoint storage service
+    pub endpoint_storage_addr: Option<String>,
+    /// JWT for authorizing requests to endpoint storage service
+    pub endpoint_storage_token: Option<String>,
+
+    /// If true, download LFC state from endpoint_storage and pass it to Postgres on startup
+    #[serde(default)]
+    pub prewarm_lfc_on_startup: bool,
 }
 
 /// Feature flag to signal `compute_ctl` to enable certain experimental functionality.