lib/ww,wcc: consolidate frontend into one syntax package (Go-compiler model, #74)

The ww compiler frontend was split across packages lex (lex+tok), ww
(ast+sym+typ), and parse — mirroring Hare's ref/hare/hare/{ast,lex,parse}.
That split's only payoff is third-party reuse, which ww has zero of: the
frontend is consumed by exactly one client, the wcc backend. The split's
cost is a wide cross-package export surface — every fn over a sibling
package's type must export it, and under separate compilation that
re-triggers check_exported_type, plus a phantom `import tok;` (tok lives
in package lex). Consolidate into ONE package lib/ww/syntax/, modelled on
Go's cmd/compile/internal/syntax. The 9 files move in (package syntax);
the intra-frontend mutual references become same-package; wcc and the
tool mains import syntax. No cstage C change (the C frontend mangles from
the source package clause). Internal data shapes (AST kinds, token model,
lexer/parser state) still mirror ref/hare/hare per rule 6/12 — only the
module decomposition collapses; the stdlib is untouched.

USER-approved (#74); spec .ai/rob-frontend-reorg.md (drew2 fidelity-
confirmed). Rule-6 carve-out documented in CLAUDE.md. Dissolves the tok
phantom import; collapses the intra-frontend export sprawl. Byte-id
rebaseline (lex.X/parse.X/ww.X -> syntax.X); cs==ww held. The residual
syntax->wcc export surface (10 types) + the unqualified-ref question are
separate follow-ups (#72/#75).

selfhost/cmd/w6c/main.ww

@@ -15,12 +15,7 @@ package main;
 import os;
 import rt;
 import strings;
-import tok;
-import lex;
-import ast;
-import parse;
-import typ;
-import sym;
+import syntax;
 import check;
 import cgen;
 import wwi;

selfhost/cmd/wcc/cgen.ww

@@ -25,10 +25,7 @@
 package wcc;
 
 import os;
-import ast;
-import tok;
-import typ;
-import sym;
+import syntax;
 import strconv;
 import strings;
 import io;

selfhost/cmd/wcc/cgendecl.ww

@@ -13,10 +13,7 @@
 package wcc;
 
 import os;
-import ast;
-import tok;
-import typ;
-import sym;
+import syntax;
 import strconv;
 
 

selfhost/cmd/wcc/cgenexpr.ww

@@ -15,10 +15,7 @@
 package wcc;
 
 import os;
-import ast;
-import tok;
-import typ;
-import sym;
+import syntax;
 import strconv;
 
 // cgfloatbits — materialise a float constant in X0: MOVQ the IEEE bits

selfhost/cmd/wcc/cgenstmt.ww

@@ -11,10 +11,7 @@
 package wcc;
 
 import os;
-import ast;
-import tok;
-import typ;
-import sym;
+import syntax;
 import strconv;
 
 // ---- statement cgen --------------------------------------------------

selfhost/cmd/wcc/cgenutil.ww

@@ -15,10 +15,7 @@
 package wcc;
 
 import os;
-import ast;
-import tok;
-import typ;
-import sym;
+import syntax;
 import strconv;
 
 // ---- variadic-call helpers (Hare-style `T...` param) -----------------

selfhost/cmd/wcc/check.ww

@@ -20,7 +20,7 @@
 package wcc;
 
 import os;
-import tok;
+import syntax;
 import strconv;
 
 type checker = struct {

selfhost/cmd/wcc/wwi.ww

@@ -21,7 +21,7 @@
 package wcc;
 
 import os;
-import tok;
+import syntax;
 import strconv;
 
 // --- byte writers ------------------------------------------------------

selfhost/cmd/wwdump/main.ww

@@ -12,12 +12,7 @@
 package main;
 
 import os;
-import tok;
-import lex;
-import ast;
-import parse;
-import typ;
-import sym;
+import syntax;
 import check;
 import cgen;
 import strconv;

selfhost/test/sym_link.ww

@@ -5,9 +5,7 @@
 
 package test;
 
-import typ;
-import ast;
-import sym;
+import syntax;
 
 export fn main() i32 = {
 	let s: *scope = newscope(nil);