ci: add GitHub Actions workflows with semantic-release auto-versioning

chore: fix all 702 clippy warnings across codebase
- auto-fix 475 via cargo clippy --fix
- fix remaining 227 manually: uninlined_format_args, redundant_closure, match_same_arms,
  underscore_binding, format_push_string, items_after_statements, needless_pass_by_value,
  clone_on_copy, case_sensitive_extension, single_match/let-else, write_with_newline,
  and other clippy lints

src/ipc/server.rs

@@ -30,6 +30,6 @@ impl IpcServer {
     /// Block until a client connects, then wrap it as a `Connection`.
     pub fn accept(&self) -> Result<Connection> {
         let (stream, _addr) = self.listener.accept()?;
-        Connection::from_stream(stream)
+        Ok(Connection::from_stream(stream))
     }
 }