feat: add extended language validators and fix tokenizer crash bugs

Expand nimcheck with validators and tokenizers for C, C++, C#, Go, Rust,
Ruby, CSS, SQL, Markdown, Dockerfile, Makefile, Kotlin, Lua, Swift,
TypeScript, and XML. Register all flavors in the validator factory and
improve auto-detection scoring for the new languages.

Fix infinite tokenizer loops that caused OOM kills: closeBracket now
advances position, finishTokenizeStep guards stalled tokenization, and
Jinja/JS tokenizers no longer double-advance on brackets.

Fix block-balance false positives in Lua (for/do) and Ruby (postfix
unless), SQL trailing-comma detection across whitespace, and Makefile
tab literals in test fixtures.

tests/fixtures/makefile/invalid.Makefile

@@ -0,0 +1,16 @@
+.PHONY: all clean
+
+CC := gcc
+CFLAGS := -O2 -Wall
+
+all: program
+
+program: main.o util.o
+	$(CC) $(CFLAGS) -o $@
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c -o $<
+	echo "unclosed
+
+clean:
+	rm -f program *.o