feat: make media inspection progressive

tests/unit/ffmpeg-engine-arguments.test.ts

@@ -7,9 +7,11 @@ import {
   MAX_PROBE_TIMEOUT_MILLISECONDS,
   MIN_PROBE_TIMEOUT_MILLISECONDS,
   MULTITHREAD_CODEC_THREAD_LIMIT,
+  canReuseProbeCapabilities,
   engineJobTimeoutMilliseconds,
   prepareEngineArguments,
   probeTimeoutMilliseconds,
+  shouldRefreshCoreBeforeProbe,
   shouldRecycleExecutionCore,
 } from '../../src/ffmpeg/EngineManager';
 
@@ -127,6 +129,40 @@ describe('probeTimeoutMilliseconds', () => {
   });
 });
 
+describe('Firefox probe core refresh policy', () => {
+  it('refreshes only affected Firefox-family runtimes', () => {
+    expect(
+      shouldRefreshCoreBeforeProbe(
+        'Mozilla/5.0 (X11; Linux x86_64; rv:142.0) Gecko/20100101 Firefox/142.0'
+      )
+    ).toBe(true);
+    expect(
+      shouldRefreshCoreBeforeProbe(
+        'Mozilla/5.0 (iPhone; CPU iPhone OS 18_6 like Mac OS X) FxiOS/142.0'
+      )
+    ).toBe(true);
+    expect(
+      shouldRefreshCoreBeforeProbe(
+        'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 Chrome/140.0 Safari/537.36'
+      )
+    ).toBe(false);
+    expect(shouldRefreshCoreBeforeProbe('')).toBe(false);
+  });
+
+  it('reuses cached capabilities only for the identical engine mode', () => {
+    expect(canReuseProbeCapabilities('multithread', 'multithread')).toBe(true);
+    expect(canReuseProbeCapabilities('single-thread', 'single-thread')).toBe(
+      true
+    );
+    expect(canReuseProbeCapabilities('multithread', 'single-thread')).toBe(
+      false
+    );
+    expect(canReuseProbeCapabilities('single-thread', 'multithread')).toBe(
+      false
+    );
+  });
+});
+
 describe('execution core recycling policy', () => {
   it('refreshes only after the bounded idle-core job budget is exhausted', () => {
     expect(shouldRecycleExecutionCore(MAX_EXECUTIONS_PER_ENGINE - 1)).toBe(