wcc+ww: //ww:module-reset boundary directive; package-less files keep module "" (#16 PREP-main)

Driver twins emit the line-comment directive only before package-less
files (peekpackage==nil); both lexers tokenize it (TK_MODRESET, appended
=87 so existing token values hold) and both parsers reset curmod — a
package-less file's decls get module "" instead of inheriting the last
bundled package (the sticky-curmod leak, task #11). Withdrawn
alternative: injecting 'package main' flips non-entry symbols
bare->main-prefixed (FFI-visible, broke 764). Codegen-neutral by proof:
bare symbols preserved, both stages emit byte-identical asm for a
directive-bearing combined. Transitional until strict-package rejects
package-less files outright. Includes 737 bad-deep pin for the
PREP-peek >2048 edge + 904/toktest rows for the new token.

cmd/ww/main.c

@@ -306,6 +306,19 @@ expand(FILE *out, const char *path, struct ImportSet *visited,
 		else        expand(out, ipath, visited, libdir);
 	}
 
+	/* #16 option-B: a package-less file's decls would otherwise inherit
+	 * the preceding bundled module's sticky curmod (parser parse.c). Emit
+	 * a curmod-reset boundary directive so the lexer/parser attribute the
+	 * file to the primary module ("") — fixes the self-import false-fire
+	 * and the leaked-prefix bug, codegen-neutral (bare symbols kept; not
+	 * `package main`, which would main-prefix them). A packaged file's own
+	 * `package` decl already sets curmod, so it needs nothing — keeping
+	 * the directive out of every tracked combined.ww. (Task #11.) */
+	{
+		char pkg[128];
+		if (!peek_package(path, pkg, sizeof pkg))
+			fputs("//ww:module-reset\n", out);
+	}
 	rewind(in);
 	int ch;
 	while ((ch = fgetc(in)) != EOF) fputc(ch, out);