tcl: conformance.sh + scoreboard, annotate classic programs

Adds lib/tcl/conformance.sh: runs .tcl programs through the epoch
protocol, compares against # expected: annotations, writes
scoreboard.json and scoreboard.md. All 3 classic programs pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/tcl/scoreboard.json

@@ -0,0 +1,10 @@
+{
+  "total": 3,
+  "passed": 3,
+  "failed": 0,
+  "programs": {
+    "assert": {"status": "PASS", "expected": "10", "got": "10"},
+    "for-each-line": {"status": "PASS", "expected": "13", "got": "13"},
+    "with-temp-var": {"status": "PASS", "expected": "100 999", "got": "100 999"}
+  }
+}