doctor: the structure check's description names sites/CONTRACT.md, which doctor has required since the instance's site handlers (#210 close); 10.0.0-beta.5

Files changed:
- CHANGES.md
- VERSION
- docs/reference/commands/instance-health.md
- tools/CONTRACT.md
- tools/chemenu/commands/doctor.py

Co-Authored-By: Claude Code <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

tools/chemenu/commands/doctor.py

@@ -947,7 +947,7 @@ def run_doctor() -> list[Check]:
     ),
     notes=(
         "Checks dependencies (Python, ripgrep), author resolution, stack version, git "
-        "identity/branch/remote, published skills, the kb/raw/reports/work/instructions "
+        "identity/branch/remote, published skills, the kb/raw/reports/work/sites/instructions "
         "structure, and generated files.",
         "Import filters (`import-filter-<name>`): one line for each `raw derive` format that "
         "reads through a package (PDF, Outlook `.msg`) - a `WARN` naming the package when it is "