Optional sections: checkpoint tracker, admin/roles, login page

- dashboard.html: each section sits in OPTIONAL:<name> BEGIN/END blocks in
  the style, markup and script, with sample answers so a page with no bot
  shows it working. Core change: setUser records the role on <body>, so CSS
  hides admin-only parts from operators.
- templates/sections.py keeps the chosen sections and deletes the rest,
  markers included; it stops on a broken marker.
- templates/sections.md: what each section needs from the host (events,
  actions, desktop slot snippets, the role re-check, the login hand-off).
- SKILL.md step 5 asks one multi-select question and runs sections.py.
- Page check: checkpoint states, admin visibility by role and assign/remove,
  login theme and hand-off to auth or the stub. Cases skip on a generated
  page without the section; the template must carry all three. The harness
  signs in when the page has a login screen.
- tests/test_sections.py: no sections leave no trace, and that page still
  passes the page check.
- Eval runner: a-empty-sections variant (all three) and per-section checks.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/evals/run_eval.py

@@ -35,6 +35,18 @@ FIXTURES = {
         "asks": [r"colou?r", r"desktop|web", r"section"],
         "never_asks": [r"\bkeep\b|restyle"],
         "brand": "#7a3cff",
+        "sections": [],
+    },
+    "a-empty-sections": {
+        "dir": "a-empty",
+        "prompt": "Build me an RPA dashboard for this project. I can't answer questions while you "
+                  "work, so here are my answers to anything the skill asks. Colours: Superbill Ember. "
+                  "Desktop or web: web. Optional sections: all three (checkpoint tracker, admin/roles "
+                  "screen, login page). The project has no auth yet.",
+        "frontend": r"^\s*(none|no\b)",
+        "asks": [r"colou?r", r"desktop|web", r"section"],
+        "never_asks": [r"\bkeep\b|restyle"],
+        "sections": ["checkpoints", "admin", "login"],
     },
 }
 
@@ -43,7 +55,7 @@ def main(fixture):
     cfg = FIXTURES[fixture]
     work = Path(tempfile.mkdtemp(prefix=f"rpa-eval-{fixture}-"))
     project = work / "project"
-    shutil.copytree(ROOT / "tests" / "fixtures" / fixture, project)
+    shutil.copytree(ROOT / "tests" / "fixtures" / cfg.get("dir", fixture), project)
     for skill in ROOT.glob("rpa-dashboard-*"):
         shutil.copytree(skill, project / ".claude" / "skills" / skill.name)
 
@@ -80,10 +92,19 @@ def main(fixture):
             spec.loader.exec_module(palette)
             t = palette.derive(cfg["brand"])
             checks["custom palette applied"] = all(f"--accent:{t[m]['--accent']}" in html for m in t)
+        if "sections" in cfg:  # chosen sections built, the others leave no trace
+            spec = importlib.util.spec_from_file_location("test_sections", ROOT / "tests" / "test_sections.py")
+            traces = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(traces)
+            for name, trace in traces.TRACES.items():
+                want = name in cfg["sections"]
+                checks[f"{name} {'built' if want else 'left no trace'}"] = bool(trace.search(html)) == want
         pc = subprocess.run([sys.executable, "-m", "pytest", str(ROOT / "tests" / "page_check"), "-q"],
                             env={**os.environ, "PAGE_CHECK_HTML": str(pages[0])}, capture_output=True, text=True)
         checks["page check passes"] = pc.returncode == 0
         page_check = pc.stdout.strip().splitlines()[-1:] if pc.stdout else [pc.stderr[-500:]]
+        if cfg.get("sections"):  # every chosen section's page check ran
+            checks["no section checks skipped"] = "skipped" not in page_check[0]
     else:
         page_check = ["no page"]