fix(wasm): finalize config without desktop shell lookup

The Node smoke test expected shaper info logs after the default logger
became errors-only. Its failure also exposed config finalization calling
an unsupported passwd lookup on wasm and returning Unexpected before
normalization completed.

Skip shell defaults on wasm, matching upstream Zig. Assert successful
config finalization and window-width clamping in the Node test. Check
shaper output directly while verifying that info logs stay suppressed.
Document these behaviors in the wasm port notes.

Test Plan:
- cargo test -p ghostty-wasm --test node (passed)
- cargo test -p ghostty-config --lib (291 passed)
- cargo clippy --target wasm32-unknown-unknown -p ghostty-wasm -- -D warnings
- cargo clippy; cargo clippy --benches; cargo clippy --tests
- cargo +nightly fmt, followed by the native Clippy checks again
- git diff --check

Related-commit: 4fb9faa667

crates/ghostty-config/src/config.rs

@@ -4594,7 +4594,9 @@ impl Config {
         // If we are missing either a command or home directory, we need
         // to look up defaults which is kind of expensive. We only do this
         // on desktop (and not in tests, like the Zig `builtin.is_test`).
-        if !cfg!(test) && (self.command.is_none() || wd == WorkingDirectory::Home) {
+        if !cfg!(any(test, target_arch = "wasm32"))
+            && (self.command.is_none() || wd == WorkingDirectory::Home)
+        {
             self.lookup_shell_defaults(probable_cli, &mut wd)?;
         }
         wd.finalize();