FlowDebugService.PredictMethodAsync resolved route targets with a sync-over-async
GetAwaiter().GetResult() inside the predictor's synchronous resolver — on the circuit's
single-threaded renderer sync context that blocked the dispatcher forever the moment a
method whose script routes to a site script was chosen (every later click and JS-interop
reply queued behind it; the page looked inert with a healthy websocket and no error).
Misdiagnosed on 2026-09-06 as a login-disabled localStorage stall. Now a resolve-and-rewalk
loop: each pass records the targets it could not answer, they are awaited between passes,
and the walk converges once a pass asks for nothing new (bounded by MaxPredictionPasses).
Regression test drives the service under a single-thread pump sync context (fails in 10 s
on the old code, passes now) plus a nested Scripts.Call resolve-across-passes test.
Claude-Session: https://claude.ai/code/session_01NcMG6xXdsJbmD2wYAgkK29
Joseph Doherty
4769e192e3