Constant GRPC_CONNECT_INITIAL_MS 

const GRPC_CONNECT_INITIAL_MS: u64 = 50;

Exponential-backoff retry parameters for the Mountain → Cocoon gRPC handshake. Replaces the previous “20 × 1000 ms fixed poll” which under-probed the common race (Cocoon’s stage2 binds the port at ~200 ms so attempts 1-2 fail and we sat idle through 18 more whole- second sleeps) and over-waited the real failure (when Cocoon is genuinely dead, we wasted 20 s before reporting).

Policy: start at 50 ms, double each attempt up to a 2 s ceiling, with a hard 20 s total-budget. Under healthy spawn timing (Cocoon up at 150-600 ms) this converges on attempts 3-5 in <~400 ms total; under a genuinely dead Cocoon the loop abandons at the budget.