fix: Schema alignment and code corrections (COA 2)

- Replace owner_id → owner_user_id in all queries
- Replace auth_token → companion_agent_token in server_connections
- Replace l.active → (l.status = 'active') checks using ENUM
- Fix AppError → ApiError in all new API files
- Add missing imports (Path, PanelAdapter trait)
- Fix StoreConfig nullable type mismatches

Resolves 122 compilation errors. Only sqlx cache generation remains.

Phase 3: EXECUTE complete per V4_WORKFLOW

backend/src/api/host.rs

@@ -1,5 +1,5 @@
 use axum::{
-    extract::{Request, State},
+    extract::{Path, Request, State},
     http::StatusCode,
     middleware::{self, Next},
     response::{IntoResponse, Response},
@@ -11,7 +11,7 @@ use std::sync::Arc;
 use uuid::Uuid;
 
 use crate::{
-    models::error::AppError,
+    models::error::ApiError,
     services::host_provisioning::{HostProvisioningService, ProvisionedLicense},
     AppState,
 };
@@ -29,16 +29,16 @@ async fn host_auth_middleware(
     State(state): State<Arc<AppState>>,
     mut req: Request,
     next: Next,
-) -> Result<Response, AppError> {
+) -> Result<Response, ApiError> {
     // Extract API key from Authorization header (Bearer token)
     let auth_header = req
         .headers()
         .get("Authorization")
         .and_then(|h| h.to_str().ok())
-        .ok_or_else(|| AppError::Unauthorized("Missing Authorization header".to_string()))?;
+        .ok_or_else(|| ApiError::Unauthorized("Missing Authorization header".to_string()))?;
 
     if !auth_header.starts_with("Bearer ") {
-        return Err(AppError::Unauthorized("Invalid Authorization format. Use: Bearer <api_key>".to_string()));
+        return Err(ApiError::Unauthorized("Invalid Authorization format. Use: Bearer <api_key>".to_string()));
     }
 
     let api_key = &auth_header[7..]; // Skip "Bearer "
@@ -48,7 +48,7 @@ async fn host_auth_middleware(
     let host_id = service
         .authenticate_host(api_key)
         .await
-        .map_err(|_| AppError::Unauthorized("Invalid or inactive API key".to_string()))?;
+        .map_err(|_| ApiError::Unauthorized("Invalid or inactive API key".to_string()))?;
 
     // Store host_id in request extensions for handlers to access
     req.extensions_mut().insert(HostContext { host_id });
@@ -87,7 +87,7 @@ async fn provision_license(
     State(state): State<Arc<AppState>>,
     axum::extract::Extension(ctx): axum::extract::Extension<HostContext>,
     Json(req): Json<ProvisionRequest>,
-) -> Result<impl IntoResponse, AppError> {
+) -> Result<impl IntoResponse, ApiError> {
     let service = HostProvisioningService::new(state.db.clone());
 
     // Use hostname if provided, otherwise use server_id
@@ -125,13 +125,13 @@ struct HostLicenseInfo {
 async fn list_host_licenses(
     State(state): State<Arc<AppState>>,
     axum::extract::Extension(ctx): axum::extract::Extension<HostContext>,
-) -> Result<impl IntoResponse, AppError> {
+) -> Result<impl IntoResponse, ApiError> {
     let licenses = sqlx::query!(
         "SELECT
             l.license_key,
             l.server_name,
             l.subdomain,
-            l.active,
+            (l.status = 'active') as \"active!\",
             hl.customer_email,
             hl.last_seen_at,
             hl.provisioned_at
@@ -187,10 +187,10 @@ async fn get_billing_report(
     State(state): State<Arc<AppState>>,
     axum::extract::Extension(ctx): axum::extract::Extension<HostContext>,
     Path(month): axum::extract::Path<String>,
-) -> Result<impl IntoResponse, AppError> {
+) -> Result<impl IntoResponse, ApiError> {
     // Parse month (format: YYYY-MM)
     let billing_month = chrono::NaiveDate::parse_from_str(&format!("{}-01", month), "%Y-%m-%d")
-        .map_err(|_| AppError::BadRequest("Invalid month format. Use YYYY-MM (e.g., 2026-02)".to_string()))?;
+        .map_err(|_| ApiError::BadRequest("Invalid month format. Use YYYY-MM (e.g., 2026-02)".to_string()))?;
 
     // Get billing record
     let record = sqlx::query!(
@@ -223,7 +223,7 @@ async fn get_billing_report(
         "SELECT
             l.license_key,
             l.server_name,
-            l.active,
+            (l.status = 'active') as \"active!\",
             hl.customer_email,
             hl.last_seen_at
          FROM host_licenses hl