test: the servers two_user starts get a Windows environment (P11c)

two_user.rs started its flagged servers with env_clear plus a Unix PATH
and HOME, no SystemRoot: on Windows Winsock cannot start without it, so
the --http door failed to bind (the server says so on stderr and serves
its pipes only, which is why "ready" still came). The tests now use the
harness's clean_env, as do evidence.rs's extract and the viewer's
command_line test. main (a8ce2e7d) merged in.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp

crates/ledger-cli/tests/evidence.rs

@@ -439,14 +439,12 @@ fn the_backfill_reads_an_old_fixtures_files_once() {
     // host does.
     books.stop();
     let run = || {
-        std::process::Command::new(env!("CARGO_BIN_EXE_wanderbooks"))
+        let mut extract = std::process::Command::new(env!("CARGO_BIN_EXE_wanderbooks"));
+        extract
             .args(["books", "extract", &books.id, "3", "--root"])
-            .arg(books.home.root())
-            .env_clear()
-            .env("PATH", "/usr/bin:/bin")
-            .env("HOME", books.home.dir.path())
-            .output()
-            .unwrap()
+            .arg(books.home.root());
+        common::clean_env(&mut extract, books.home.dir.path());
+        extract.output().unwrap()
     };
     let before = books.journal();
     let out = run();