fix(quick-dev): scope render/ whitelist to bmad-quick-dev

The previous INSTALL_ONLY_PATHS entry 'render/' was a blanket prefix
that let every {project-root}/_bmad/render/... reference in any skill
slip past validation. Narrow to 'render/bmad-quick-dev/' so only this
skill's render buffer is whitelisted. Future skills adopting the
stdout-dispatch renderer pattern add their own entries explicitly.

Part of plan-quick-dev-python-config-hardening.md (F6).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: alexeyv

tools/validate-file-refs.js

@@ -80,7 +80,7 @@ function escapeTableCell(str) {
 }
 
 // Path prefixes/patterns that only exist in installed structure, not in source
-const INSTALL_ONLY_PATHS = ['_config/', 'custom/', 'render/'];
+const INSTALL_ONLY_PATHS = ['_config/', 'custom/', 'render/bmad-quick-dev/'];
 
 // Files that are generated at install time and don't exist in the source tree
 const INSTALL_GENERATED_FILES = ['config.yaml', 'config.user.yaml'];