fix: return JSON errors from create_job and add admin job-slot grant endpoint

create_job returned plain-text bodies on every failure branch except
quota-exhausted, so the frontend's res.json() silently failed and always
showed a generic "Failed to create job" message regardless of the real
cause (company not approved, quota exhausted, DB error).

Also adds PATCH /api/admin/companies/{id}/job-slots as a manual top-up
for purchased_job_slots, since no self-serve purchase flow exists yet.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/companies/src/handlers/admin.rs

@@ -21,6 +21,7 @@ pub fn router() -> Router<AppState> {
         .route("/{id}/approve", patch(approve_company))
         .route("/{id}/reject", patch(reject_company))
         .route("/{id}/suspend", patch(suspend_company))
+        .route("/{id}/job-slots", patch(grant_job_slots))
         .route("/jobs", get(list_jobs))
         .route("/jobs/{id}/approve", post(approve_job))
         .route("/jobs/{id}/reject", post(reject_job))
@@ -224,6 +225,36 @@ async fn suspend_company(
     Ok(Json(serde_json::json!({ "status": "SUSPENDED" })))
 }
 
+#[derive(Deserialize)]
+pub struct GrantJobSlotsPayload {
+    pub slots: i32,
+}
+
+/// Manual top-up for `purchased_job_slots` while the self-serve purchase flow
+/// (TraceCoin/PayU) doesn't exist yet. Support-only unblock path.
+async fn grant_job_slots(
+    _auth: AuthUser,
+    State(state): State<AppState>,
+    Path(id): Path<Uuid>,
+    Json(payload): Json<GrantJobSlotsPayload>,
+) -> Result<impl IntoResponse, (StatusCode, String)> {
+    if payload.slots <= 0 {
+        return Err((StatusCode::BAD_REQUEST, "slots must be a positive integer".to_string()));
+    }
+
+    let new_total: i32 = sqlx::query_scalar(
+        "UPDATE company_profiles SET purchased_job_slots = purchased_job_slots + $1, updated_at = NOW() WHERE id = $2 RETURNING purchased_job_slots"
+    )
+    .bind(payload.slots)
+    .bind(id)
+    .fetch_optional(&state.pool)
+    .await
+    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?
+    .ok_or((StatusCode::NOT_FOUND, "Company not found".to_string()))?;
+
+    Ok(Json(serde_json::json!({ "purchased_job_slots": new_total })))
+}
+
 async fn list_jobs(
     _auth: AuthUser,
     State(state): State<AppState>,

apps/companies/src/handlers/mod.rs

@@ -185,17 +185,24 @@ async fn create_job(
 ) -> impl IntoResponse {
     let company = match CompanyRepository::get_by_user_id(&state.pool, auth.user_id).await {
         Ok(Some(c)) => c,
-        _ => return (StatusCode::NOT_FOUND, "Company not found").into_response(),
+        Ok(None) => return (StatusCode::NOT_FOUND, Json(serde_json::json!({ "error": "Company not found" }))).into_response(),
+        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": e.to_string() }))).into_response(),
     };
 
     if company.status != "APPROVED" {
-        return (StatusCode::FORBIDDEN, "Company profile approval is required before posting jobs").into_response();
+        return (
+            StatusCode::FORBIDDEN,
+            Json(serde_json::json!({
+                "error": "Company profile approval is required before posting jobs",
+                "code": "COMPANY_NOT_APPROVED"
+            })),
+        ).into_response();
     }
 
     // --- New Quota Logic ---
     let jobs_this_month = match JobRepository::count_by_company_id_this_month(&state.pool, company.id).await {
         Ok(count) => count,
-        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
+        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": e.to_string() }))).into_response(),
     };
 
     if jobs_this_month >= 1 {
@@ -221,7 +228,7 @@ async fn create_job(
 
         if let Err(e) = deduct_result {
             tracing::error!("Failed to deduct job slot: {}", e);
-            return (StatusCode::INTERNAL_SERVER_ERROR, "Failed to deduct quota").into_response();
+            return (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": "Failed to deduct quota" }))).into_response();
         }
     }
     // -----------------------
@@ -251,7 +258,7 @@ async fn create_job(
             }
             (StatusCode::CREATED, Json(job)).into_response()
         }
-        Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
+        Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": e.to_string() }))).into_response(),
     }
 }