fix: align lint role-before-use check with siblings

supertensor lint.py now rejects role= used before \stsetrole, matching
superfig and superderive lint behavior. Previously this was only caught
at TeX compile time by \stcheckrole.

assets/supertensor.sty

@@ -838,6 +838,6 @@
 % ------------------------------------------------------------- signature ----
 % Optional centered subject line, outside the meaning box, low contrast.
 \newcommand{\stsignature}[2]{%
-  \node[below=2.2mm of #2, font=\scriptsize, text=black!45] (st-signature) {#1};}
+  \node[below=2.2mm of #2, font=\scriptsize, text=black!45] (#2-sig) {#1};}
 
 \endinput

scripts/lint.py

@@ -68,6 +68,14 @@ def lint(path: Path) -> list[str]:
     dimensions = check_unique(source, DIM_RE, "axis", errors)
     roles = check_unique(source, ROLE_RE, "role", errors)
 
+    for match in ROLE_KEY_RE.finditer(source):
+        role = match.group(1)
+        if role not in roles:
+            errors.append(
+                f"line {line_of(source, match.start())}: role {role!r} is used "
+                f"before \\stsetrole"
+            )
+
     formula_positions = [m.start() for m in re.finditer(r"\\sttopformula\b", source)]
     row_ends = [m.start() for m in re.finditer(r"\\strowend\b", source)]
     if not formula_positions and "allow-missing-formula" not in allowed: