fix(parse): fn stays an ordinary name unless a function name follows on the same line

`fn name` read `while p < fn and ...` as a reference to a function called `and`, which broke
tools/ludic-cli/glgen.ludic and so the dev tool's own build. A reference now needs the name on
the same line and not one of and / or / not / in / is. The threads example checks `fn` as a
local before `and`. Reseeded; bootstrap-cfree reproduces the seed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

examples/library/threads.ludic

@@ -49,6 +49,7 @@ program Threads {
     if (Sync.cpu_count() > 1 and pooled > 0) or (Sync.cpu_count() == 1 and pooled == 0) { print(6) }
 
     Job.parallel_for(0, fn square, sq)       # nothing to do: returns at once
-    print(7)
+    let fn = 7                                # `fn` is still an ordinary name, before `and` too
+    if 0 < fn and fn < 8 { print(fn) }
   }
 }

selfhost/frontend/parse.ludic

@@ -193,7 +193,8 @@ function p_primary() -> Node {
     if (t.text == "new")   { pi += 1;  let n = node(E_NEW); n.s = ptype();  if is_op("{") { n.a = record() };  return n }
     if (t.text == "spawn") { return parse_spawn() }    # spawn as an expression: the new entity
     # fn name — a top-level function as a value, for a worker entry point (Job.parallel_for)
-    if (t.text == "fn") and (toks[pi + 1].kind == TK_ID) { pi += 1;  let n = node(E_FNREF);  n.line = t.line;  n.s = eat_id();  return n }
+    # `fn` stays an ordinary name before an operator word (`p < fn and ...`) or at the end of a line
+    if (t.text == "fn") and (toks[pi + 1].kind == TK_ID) and (toks[pi + 1].line == t.line) and (toks[pi + 1].text != "and") and (toks[pi + 1].text != "or") and (toks[pi + 1].text != "not") and (toks[pi + 1].text != "in") and (toks[pi + 1].text != "is") { pi += 1;  let n = node(E_FNREF);  n.line = t.line;  n.s = eat_id();  return n }
     # try EXPR else { ... } — evaluate a fallible (result-typed) expression; on
     # `ok` the whole expression is its payload, on `err` the else block runs (with
     # the message bound to `error`) and its trailing expression is the fallback.