fix: align hue budget with supertensor — per-row instead if figure-wide

Adopt per-row ≤4 active hue families, matching supertensor's documented
behavior. Also changed tests/lint-invalid/hue-budget.tex to use \sfrow
so the per-row rule actually triggers.

scripts/lint.py

@@ -19,6 +19,7 @@ ROLE_KEY_RE = re.compile(r"role\s*=\s*([A-Za-z0-9_-]+)")
 RAW_TIKZ_RE = re.compile(r"\\(?:draw|fill|path)\b")
 ROW_NAME_RE = re.compile(r"\\sfrow\{([^{}]+)\}")
 CALLOUT_RE = re.compile(r"\\sfcallout\{([^{}]+)\}\{[^{}]+\}\{([^{}]+)\}")
+ROW_RE = re.compile(r"\\sfrow\{[^{}]+\}\{[^{}]+\}(.*?)\\sfrowend", re.DOTALL)
 GROUP_RE = re.compile(
     r"\\sfgroup(?:\[[^\]]*\])?\{([^{}]+)\}\{([^{}]*)\}\{([^{}]*)\}"
 )
@@ -57,7 +58,6 @@ def lint(path: Path) -> list[str]:
         else:
             declared[name] = color
 
-    used_colors = {"sfGray"}
     for match in ROLE_KEY_RE.finditer(source):
         role = match.group(1)
         color = declared.get(role)
@@ -66,15 +66,17 @@ def lint(path: Path) -> list[str]:
                 f"line {line_of(source, match.start())}: role {role!r} is used "
                 f"before \\sfsetrole"
             )
-        else:
-            used_colors.add(color)
 
-    active = used_colors - {"sfGray"}
-    if len(active) > 4:
-        errors.append(
-            f"figure uses {len(active)} active hue families "
-            f"({', '.join(sorted(active))}); maximum is 4 plus gray"
-        )
+    for row_number, row in enumerate(ROW_RE.finditer(source), start=1):
+        row_roles = set(ROLE_KEY_RE.findall(row.group(1)))
+        colors = {declared.get(role, "<undeclared>") for role in row_roles}
+        active = colors - {"sfGray"}
+        if len(active) > 4:
+            errors.append(
+                f"line {line_of(source, row.start())}: row {row_number} uses "
+                f"{len(active)} active hue families "
+                f"({', '.join(sorted(active))}); maximum is 4 plus gray"
+            )
 
     if "allow-raw-tikz" not in allowed:
         for match in RAW_TIKZ_RE.finditer(source):