fix(maintenance): v0.18.2 — four confirmed-live fixes

1. Cost-reporter SQL: phpcs:ignore annotations were embedded inside two SQL
   string literals (get_daily_spend, get_spend_by_stage), causing MariaDB to
   reject both queries and break the Metrics & Costs admin page. Moved annotations
   above the prepare() calls. Regression tests added to CostReporterTest.

2. Collector failure observability: catch block in collect_from_all_sources() now
   logs structured meta (model slug, HTTP status parsed from exception message,
   first 200 chars of error body) so outage incidents are diagnosable post-hoc.

3. run_stages.agent_role back-write: Pipeline_Runner, Article_Worker, and
   Content_Generator were calling Run_Stage_State::start() with agent_role=''.
   All start() call sites now pass Stage_Display_Map::default_agent_role(stage).
   Role written at INSERT only; ON DUPLICATE KEY UPDATE does not include
   agent_role — idempotency-key semantics on resume are unchanged.

4. Runware float deprecation: normalize_seed() applied % to a float
   (microtime(true) * 1000), triggering PHP 8 deprecation on every image
   generation. Fixed with (int) round(...) before the modulo operator.

Refs: convo/prautoblogger/threads/2026-06-pipeline-v2-phase1/25-cto-v0182-maintenance.md
Agent-Session: prab-v0182-maintenance-20260612

includes/providers/class-runware-image-support.php

@@ -181,7 +181,8 @@ class PRAutoBlogger_Runware_Image_Support {
 	 */
 	public function normalize_seed( ?int $seed ): int {
 		if ( null === $seed || $seed < 1 ) {
-			$derived = (int) ( ( microtime( true ) * 1000 ) % 2147483647 );
+			// Cast to int before modulo — float % int is deprecated in PHP 8 (v0.18.2).
+			$derived = (int) round( microtime( true ) * 1000 ) % 2147483647;
 			return $derived > 0 ? $derived : 1;
 		}
 		return $seed;