w6c+wwstage: wwstage alias-aggregate-return loud-stop + #276 citations (#272 review)

Review fixes for the #272 fold (reviewer272b gate; rob+ken ruling). Bundled
because the wwstage catch-all message carries the citation and the combined.ww
regen covers both .ww edits.

- wwstage cgreturn close-by-construction catch-all keyed on the SYNTACTIC
  return-type node (N_TARRAY / N_TNAME+structlookup), so a named-alias
  aggregate return type (type a=[N]T / type a=struct) bypassed both the
  handling arms AND the loud-stop, falling to the scalar default = silent
  segfault/truncation; cstage (type_chase_named at all 4 N_RETURN sites)
  stayed correct. Re-key the catch-all on the RESOLVED tinfo (chase
  TY_NAMED -> TY_ARRAY/TY_STRUCT) so wwstage LOUD-STOPS (rule 7) instead of
  miscompiling. cstage stays correct; the full wwstage tinfo-kind dispatch
  (align UP, byte-id) is #277. Established wwstage-stricter divergence
  (cf #264), no bootstrap consumer (990-997 green).

- #276 citations at-site (both stages): the cstage >24B array-literal return
  loud-stop and the <=24B STRUCT global-receive residual now cite #276. The
  wwstage >24B array-literal routes through the tinfo-keyed catch-all
  (#272/#276/#277). Correction: ALL <=24B struct globals truncate
  symmetrically (byte-id-clean), not only float-bearing -- #276 broadened.

- Cosmetic: fix a double-encoded U+2264 (mojibake) in the cgen.c commit-2
  comment.

combined.ww regenerated (#110).

selfhost/cmd/wcc/cgenexpr.ww

@@ -7475,9 +7475,11 @@ fn cgassign(c: *cgen, n: *node) void = {
 				// transport); the scalar store below would truncate to
 				// MOVQ AX, g(SB). LEAQ the symbol into DI, store the
 				// full+tail words. Mirror of cstage cgen.c ≤24B global
-				// arm. A ≤24B STRUCT global receive can be float-class
-				// (X0/X1) so it stays at its pre-existing behaviour — no
-				// consumer (rule-10 aligned with cstage).
+				// arm. #276: a ≤24B STRUCT global receive can be
+				// float-class (X0/X1) so it stays at its pre-existing
+				// behaviour — no consumer (rule-10 aligned with cstage;
+				// note non-float struct globals also truncate symmetrically
+				// here, byte-id-clean — #276 covers both).
 				if (n.op == tkind.TK_ASSIGN && n.rhs != nil
 				    && n.rhs.kind == nkind.N_CALL && lvftn != nil
 				    && lvftn.kind == nkind.N_TARRAY) {