fix(core): Resolve TypeScript strict mode and ES client API compatibility issues for v3.0.0

- Fix ES client v8+ API: use document/doc instead of body for index/update operations
- Add type assertions (as any) for ES client ILM, template, and search APIs
- Fix strict null checks with proper undefined handling (nullish coalescing)
- Fix MetricsCollector interface to match required method signatures
- Fix Logger.error signature compatibility in plugins
- Resolve TermsQuery type index signature conflict
- Remove sourceMap from tsconfig (handled by tsbuild with inlineSourceMap)

ts/core/observability/logger.ts

@@ -199,9 +199,26 @@ export class Logger {
 
   /**
    * Log at ERROR level
+   *
+   * Accepts either:
+   * - error(message, Error, meta) - explicit error with optional metadata
+   * - error(message, meta) - error context as metadata (error property extracted)
    */
-  error(message: string, error?: Error, meta?: Record<string, unknown>): void {
-    this.log(LogLevel.ERROR, message, meta, error);
+  error(message: string, errorOrMeta?: Error | Record<string, unknown>, meta?: Record<string, unknown>): void {
+    if (errorOrMeta instanceof Error) {
+      this.log(LogLevel.ERROR, message, meta, errorOrMeta);
+    } else if (errorOrMeta && typeof errorOrMeta === 'object') {
+      // Extract error from meta if present
+      const errorValue = (errorOrMeta as Record<string, unknown>).error;
+      const extractedError = errorValue instanceof Error
+        ? errorValue
+        : typeof errorValue === 'string'
+          ? new Error(errorValue)
+          : undefined;
+      this.log(LogLevel.ERROR, message, errorOrMeta, extractedError);
+    } else {
+      this.log(LogLevel.ERROR, message);
+    }
   }
 
   /**

ts/core/observability/metrics.ts

@@ -529,6 +529,42 @@ export class MetricsCollector {
     return histogram;
   }
 
+  /**
+   * Record a counter increment (convenience method for plugins)
+   */
+  recordCounter(name: string, value: number = 1, labels: Labels = {}): void {
+    let counter = this.registry.get(name) as Counter | undefined;
+    if (!counter) {
+      counter = new Counter(name, `Counter: ${name}`, Object.keys(labels));
+      this.registry.register(counter);
+    }
+    counter.inc(labels, value);
+  }
+
+  /**
+   * Record a histogram observation (convenience method for plugins)
+   */
+  recordHistogram(name: string, value: number, labels: Labels = {}): void {
+    let histogram = this.registry.get(name) as Histogram | undefined;
+    if (!histogram) {
+      histogram = new Histogram(name, `Histogram: ${name}`, Object.keys(labels));
+      this.registry.register(histogram);
+    }
+    histogram.observe(value, labels);
+  }
+
+  /**
+   * Record a gauge value (convenience method for plugins)
+   */
+  recordGauge(name: string, value: number, labels: Labels = {}): void {
+    let gauge = this.registry.get(name) as Gauge | undefined;
+    if (!gauge) {
+      gauge = new Gauge(name, `Gauge: ${name}`, Object.keys(labels));
+      this.registry.register(gauge);
+    }
+    gauge.set(value, labels);
+  }
+
   /**
    * Export all metrics in Prometheus format
    */

ts/core/observability/tracing.ts

@@ -311,10 +311,16 @@ export class InMemoryTracer implements Tracer {
     const parts = traceparent.split('-');
     if (parts.length !== 4) return null;
 
+    const traceId = parts[1];
+    const spanId = parts[2];
+    const flagsStr = parts[3];
+
+    if (!traceId || !spanId || !flagsStr) return null;
+
     return {
-      traceId: parts[1],
-      spanId: parts[2],
-      traceFlags: parseInt(parts[3], 16),
+      traceId,
+      spanId,
+      traceFlags: parseInt(flagsStr, 16),
     };
   }
 }