Add machine deletion API with uninstall command support

- Add AdminCommand message to protobuf (uninstall, restart, update)
- Add DELETE /api/machines/:agent_id endpoint with options:
  - ?uninstall=true - send uninstall command to online agent
  - ?export=true - return session history before deletion
- Add GET /api/machines/:agent_id/history endpoint for history export
- Add GET /api/machines endpoint to list all machines
- Handle AdminCommand in agent session handler
- Handle ADMIN_UNINSTALL error in agent main loop to trigger uninstall

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

server/src/api/mod.rs

@@ -1,13 +1,14 @@
 //! REST API endpoints
 
 use axum::{
-    extract::{Path, State},
+    extract::{Path, State, Query},
     Json,
 };
-use serde::Serialize;
+use serde::{Deserialize, Serialize};
 use uuid::Uuid;
 
 use crate::session::SessionManager;
+use crate::db;
 
 /// Viewer info returned by API
 #[derive(Debug, Serialize)]
@@ -88,3 +89,120 @@ pub async fn get_session(
 
     Ok(Json(SessionInfo::from(session)))
 }
+
+// ============================================================================
+// Machine API Types
+// ============================================================================
+
+/// Machine info returned by API
+#[derive(Debug, Serialize)]
+pub struct MachineInfo {
+    pub id: String,
+    pub agent_id: String,
+    pub hostname: String,
+    pub os_version: Option<String>,
+    pub is_elevated: bool,
+    pub is_persistent: bool,
+    pub first_seen: String,
+    pub last_seen: String,
+    pub status: String,
+}
+
+impl From<db::machines::Machine> for MachineInfo {
+    fn from(m: db::machines::Machine) -> Self {
+        Self {
+            id: m.id.to_string(),
+            agent_id: m.agent_id,
+            hostname: m.hostname,
+            os_version: m.os_version,
+            is_elevated: m.is_elevated,
+            is_persistent: m.is_persistent,
+            first_seen: m.first_seen.to_rfc3339(),
+            last_seen: m.last_seen.to_rfc3339(),
+            status: m.status,
+        }
+    }
+}
+
+/// Session record for history
+#[derive(Debug, Serialize)]
+pub struct SessionRecord {
+    pub id: String,
+    pub started_at: String,
+    pub ended_at: Option<String>,
+    pub duration_secs: Option<i32>,
+    pub is_support_session: bool,
+    pub support_code: Option<String>,
+    pub status: String,
+}
+
+impl From<db::sessions::DbSession> for SessionRecord {
+    fn from(s: db::sessions::DbSession) -> Self {
+        Self {
+            id: s.id.to_string(),
+            started_at: s.started_at.to_rfc3339(),
+            ended_at: s.ended_at.map(|t| t.to_rfc3339()),
+            duration_secs: s.duration_secs,
+            is_support_session: s.is_support_session,
+            support_code: s.support_code,
+            status: s.status,
+        }
+    }
+}
+
+/// Event record for history
+#[derive(Debug, Serialize)]
+pub struct EventRecord {
+    pub id: i64,
+    pub session_id: String,
+    pub event_type: String,
+    pub timestamp: String,
+    pub viewer_id: Option<String>,
+    pub viewer_name: Option<String>,
+    pub details: Option<serde_json::Value>,
+    pub ip_address: Option<String>,
+}
+
+impl From<db::events::SessionEvent> for EventRecord {
+    fn from(e: db::events::SessionEvent) -> Self {
+        Self {
+            id: e.id,
+            session_id: e.session_id.to_string(),
+            event_type: e.event_type,
+            timestamp: e.timestamp.to_rfc3339(),
+            viewer_id: e.viewer_id,
+            viewer_name: e.viewer_name,
+            details: e.details,
+            ip_address: e.ip_address,
+        }
+    }
+}
+
+/// Full machine history (for export)
+#[derive(Debug, Serialize)]
+pub struct MachineHistory {
+    pub machine: MachineInfo,
+    pub sessions: Vec<SessionRecord>,
+    pub events: Vec<EventRecord>,
+    pub exported_at: String,
+}
+
+/// Query parameters for machine deletion
+#[derive(Debug, Deserialize)]
+pub struct DeleteMachineParams {
+    /// If true, send uninstall command to agent (if online)
+    #[serde(default)]
+    pub uninstall: bool,
+    /// If true, include history in response before deletion
+    #[serde(default)]
+    pub export: bool,
+}
+
+/// Response for machine deletion
+#[derive(Debug, Serialize)]
+pub struct DeleteMachineResponse {
+    pub success: bool,
+    pub message: String,
+    pub uninstall_sent: bool,
+    pub history: Option<MachineHistory>,
+}