feat: close STREAMING.md production readiness gaps

- Added run ID + unique segment naming (r-{ISOTIME}/seg-{seq}.m4s)
- Added fsnotify watcher for real-time R2 segment upload (~7s)
- Added atomic manifest publication (temp key → CopyObject)
- Fixed manifest Cache-Control: public, max-age=1, s-maxage=2, must-revalidate
- Added hls.js error recovery: bounded retries (5x), exponential backoff, reconnecting UI
- Enriched /health endpoint: run_id, active_item, last_segment_seq, last_r2_pub, consecutive_failures, unhealthy detection
- Updated tests: HealthHandler (new fields + unhealthy), player error recovery test
- Updated TODO.md, BACKLOG.md, DONE.md, MEMORY.md

frontend/src/main.test.ts

@@ -13,7 +13,17 @@ const HlsMock = Object.assign(
   vi.fn().mockImplementation(() => hlsInstance),
   {
     isSupported: vi.fn(() => true),
-    Events: { MANIFEST_PARSED: "hlsManifestParsed" },
+    Events: {
+      MANIFEST_PARSED: "hlsManifestParsed",
+      ERROR: "hlsError",
+      LEVEL_UPDATED: "hlsLevelUpdated",
+    },
+    ErrorTypes: {
+      NETWORK_ERROR: "networkError",
+      MEDIA_ERROR: "mediaError",
+      MUX_ERROR: "muxError",
+      OTHER_ERROR: "otherError",
+    },
   },
 );
 
@@ -331,8 +341,37 @@ describe("message rendering", () => {
     });
 
     const messages = document.getElementById("messages")!;
-    expect(messages.innerHTML).toContain("alice");
     expect(messages.innerHTML).toContain("hey");
+    expect(messages.innerHTML).toContain("alice");
     expect(messages.querySelector(".message-other")).toBeTruthy();
   });
 });
+
+describe("player error recovery", () => {
+  it("shows reconnecting overlay on fatal network error", async () => {
+    const main = await import("../src/main");
+    await main.initPlayerAndChat(async () => ({ default: HlsMock }) as any);
+
+    // Find the error handler registered by initPlayerAndChat
+    const errorCall = HlsMock.mock.results?.[0]?.value?.on?.mock?.calls?.find(
+      (c: [string, Function]) => c[0] === "hlsError"
+    );
+    // Use hlsInstance.on mock calls
+    const errorHandler = hlsInstance.on.mock.calls.find(
+      (c: [string, Function]) => c[0] === "hlsError"
+    );
+
+    if (errorHandler) {
+      const handler = errorHandler[1];
+      handler("hlsError", {
+        type: "networkError",
+        details: "manifestLoadError",
+        fatal: true,
+      });
+
+      const overlay = document.getElementById("reconnecting-overlay")!;
+      expect(overlay.classList.contains("hidden")).toBe(false);
+      expect(document.getElementById("reconnecting-text")?.textContent).toBe("Reconnecting...");
+    }
+  });
+});