Retry policy for an LSP reconfigure-on-focus follower: remember only deterministic failures, scope invalidation to build membership

When an editor reconfigures a language server on each file focus (for example slang-server setBuildFile per testbench), keep three outcomes apart. (1) Deterministic failure: the server answered and elaborated nothing. Remember it so it is not rebuilt on every focus. (2) Transient error: the RPC threw, ssh timed out, the server restarted, or the command is unsupported. Do NOT remember it; put back the previous compilation, show the message and retry on the next focus. (3) An unanswered follow-up query (scope or hierarchy) is not proof of failure. Clear the remembered failure only when a file saved or reloaded belongs to that build: the .f itself, a nested -f/-F, or a source resolved against the server root and compared in the server path form (realpath locally, standardized path remotely). If the build is not known yet or nests command files you do not parse, treat it as included. Without the scoping, every save of any source triggers a rebuild of every broken profile.