ui: loading states, player failure overlay + retry, toasts, back nav, full history page with delete

Bundle 1-4+7 from PLAN.md: skeleton loaders, player Loading/Buffering/fatal overlay with Retry, action toasts, back-to-home crumb + logo fix, ?history full-history view with per-entry delete (GET /api/history?all=1, DELETE /api/history). 14/14 tests green.

tests/run.py

@@ -23,7 +23,7 @@ ROOT = Path(__file__).parent.parent
 PORT = 8399
 BASE = f"http://127.0.0.1:{PORT}"
 USERS = (("admin", "adminpw12345"), ("alice", "alicepw12345"), ("bob", "bobpw12345"),
-         ("dave", "davepw12345"))
+         ("dave", "davepw12345"), ("erin", "erinpw12345"))
 
 
 def _wait_ready():
@@ -74,6 +74,8 @@ def main():
             print("ok browser (playwright)")
             asyncio.run(test_browser.test_login_ui())
             asyncio.run(test_browser.test_video_plays_behind_auth())
+            asyncio.run(test_browser.test_history_page_and_delete())
+            asyncio.run(test_browser.test_stream_failure_retry())
 
         print("ALL TESTS PASSED")
     finally: