fix(bundler): dump_yaml writes literal UTF-8 (allow_unicode=True) (#3660)

dump_yaml called yaml.safe_dump without allow_unicode=True, so non-ASCII
content was written as \xNN / \uXXXX escapes instead of literal UTF-8 — a
round-trip readability loss for bundle config. The centralized helper
_utils.dump_frontmatter and the extensions/presets config writers all pass
allow_unicode=True; align dump_yaml with them.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/specify_cli/bundler/lib/yamlio.py

@@ -60,7 +60,13 @@ def dump_yaml(path: Path, data: Any, *, within: Path | None = None) -> Path:
     try:
         path.parent.mkdir(parents=True, exist_ok=True)
         with path.open("w", encoding="utf-8") as handle:
-            yaml.safe_dump(data, handle, sort_keys=False, default_flow_style=False)
+            yaml.safe_dump(
+                data,
+                handle,
+                sort_keys=False,
+                default_flow_style=False,
+                allow_unicode=True,
+            )
     except OSError as exc:
         raise BundlerError(f"Could not write {path}: {exc}") from exc
     return path