fix: prevent reconnect loops during server stalls - #5561

💭 Looking at the changes across the codebase, the prior concern about the shell cache being process-global has been resolved by converting it to a Context.Reference. I'm checking the current state of the modified files to confirm everything is properly addressed. The Context import is placed after the local import from ./hostProcess.ts, which violates the canonical file order convention that puts all imports first. This is a minor style issue worth noting since the convention explicitly specifies the expected import ordering. Looking at externalLauncher, it seems straightforward, though I'm noting the use of Effect.cachedWithTTL — wondering if that requires a Scope in Effect 4. Moving into supervisor.ts and shell.ts, I'm checking the imports and whether they follow conventions. The type-only import for RpcSession looks fine based on the guidelines, but I'm reviewing the broader import patterns to make sure everything aligns. Looking through the code changes to verify there are no convention violations. The supervisor changes use Ref properly, the ChatView update adds a toast notification in a handler without introducing any problematic patterns, and observability.ts exports pure functions. The cache dependency that was previously flagged has been moved to Context.Reference, but I'm now questioning whether CommandResolutionCache as a mutable Map in the environment constitutes hiding a dependency in module globals.