wwi: derive decl-less module's .wwi package leaf from parse-stamped path (#11)

wwi_emit took the .wwi `package` leaf from the first primary decl's module tag;
a fully empty primary module body (zero decls) had none, so the leaf stayed the
literal default "main" and the importer rejected it ("package main does not
match import path <leaf>"). The module identity is only available at parse time
(curmod is overwritten by imported //ww:module sections before emit), so stamp
the primary path onto the N_FILE node (TK_MODULE and TK_MODRESET rp!=NULL sites,
only-if-empty so a bare-reset `package main` root stays "main") and, when the
decl-scan finds no leaf, fall back to that stamped path. Symmetric cstage+
selfhost; both detect scan-miss via the same found-flag so the emitted .wwi
stays byte-identical.

Regression: test/wcc/989_wwileaf_run.c, table-driven over {empty body,
comment-only, nested a.b.c} decl-less shapes, non-vacuity proven.

lib/ww/syntax/parse.ww

@@ -448,6 +448,12 @@ export fn parsefile(p: *parser) *node = {
 				};
 			} else {
 				p.curmod = name;
+				// #11: stamp the primary module identity on the
+				// N_FILE node so wwi_emit can derive the `package`
+				// leaf even when the body carries zero module-tagged
+				// decls. Primary identity only; never the imported
+				// boundary (TK_MODPATH).
+				if (f.nmod.len == 0) { f.nmod = name; };
 			};
 			continue;
 		};
@@ -483,6 +489,11 @@ export fn parsefile(p: *parser) *node = {
 			if (rp.len != 0) {
 				p.curmod = rp;
 				p.resetmod = rp;
+				// #11: path-carrying reset is a primary body identity
+				// (sep); stamp it for the wwi leaf fallback. A bare
+				// reset (rp empty) is the root/package-less boundary
+				// and MUST keep the "main" default — so don't stamp.
+				if (f.nmod.len == 0) { f.nmod = rp; };
 			} else {
 				let empty: str;
 				empty.ptr = nil;