fix(v0183): GA4 SQL fix + manual-run resilience + honest status

R1: move phpcs:ignore out of SQL string in class-analysis-prompts.php:81
    (same pattern as v0.18.2 cost-reporter fix). GA4 self-improvement loop
    has returned empty context on every pipeline run since v0.16.0 — this
    restores get_performance_context() to the LLM. Sibling occurrence also
    fixed in class-post-assembler.php:112.

R2(a): update_generation_stage() now renews STATUS_TTL on every stage call
    so the transient outlasts long LLM calls during background runs.

R2(b): on_ajax_generation_status() detects lock-held-but-transient-gone
    when lock age > STATUS_TTL (= Hostinger background-process kill).
    Marks stuck run failed, releases lock, returns status:error with
    'infrastructure timeout' message. Daily reaper remains the backstop.

R3: when transient absent but lock held within TTL, return status:running
    (with started_at from lock) instead of status:idle.

Executor split: class-executor.php was 351 lines (>300). AJAX generation
    handlers extracted to new class-generation-status-poller.php (260 lines);
    executor now 226 lines. Public hook wiring unchanged via delegation.
    Generation_Lock gains get_acquired_at() for R2b/R3 lock-age checks.

Tests: AnalysisPromptsTest (regression SQL + behavioral context shaping),
       GenerationStatusPollerTest (R2a TTL renewal, R2b abort, R3 running,
       idle path).

Closes: R1 (analysis-prompts SQL), R2 (manual-run resilience), R3 (honest status)
Version: 0.18.3
Agent-Session: prab-v0183-20260612

includes/class-generation-lock.php

@@ -76,6 +76,29 @@ class PRAutoBlogger_Generation_Lock {
 		return null !== $row;
 	}
 
+	/**
+	 * Get the Unix timestamp when the lock was acquired, or null if not held.
+	 *
+	 * Returns null when the lock is not set. The timestamp is the value written
+	 * by acquire() — used by the status poller to detect infrastructure-timeout
+	 * runs (lock held longer than STATUS_TTL → background PHP process died).
+	 *
+	 * @return int|null Unix timestamp, or null when the lock is absent.
+	 */
+	public static function get_acquired_at(): ?int {
+		global $wpdb;
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
+		$row = $wpdb->get_var(
+			$wpdb->prepare(
+				"SELECT option_value FROM {$wpdb->options} WHERE option_name = %s LIMIT 1",
+				self::LOCK_NAME
+			)
+		);
+
+		return null !== $row ? (int) $row : null;
+	}
+
 	/**
 	 * Release the generation mutex.
 	 *