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).

lib/ww/syntax/ast.ww

@@ -1,4 +1,4 @@
-// lib/ww/ast.ww — port of cmd/wcc/ast.c (Node defs + printer).
+// lib/ww/syntax/ast.ww — port of cmd/wcc/ast.c (Node defs + printer).
 //
 // Status: AST printer is fully ported. Constructor `newnode` is here.
 // The parser (parse.ww) is currently minimal — see its file header.
@@ -7,11 +7,10 @@
 // by value (8 *node pointers + 2 strs + a few ints), so callers always
 // hand around `*node`. Only `newnode` allocates and returns a *node.
 
-package ww;
+package syntax;
 
 import os;
 import strconv;
-import tok;
 
 // ---- Nkind ------------------------------------------------------------
 //

lib/ww/syntax/asttest.ww

@@ -1,6 +1,6 @@
 // asttest — functional-equivalence pin for [[nkname]] after the
 // if-ladder → switch fold (struct fold S2). Run with
-// `ww run lib/ww/asttest.ww`.
+// `ww run -I lib/ww lib/ww/syntax/asttest.ww`.
 //
 // nkname is checked against every nkind value (the full ladder the
 // switch replaced) plus the out-of-band fallback ("?"). A failing row
@@ -10,7 +10,7 @@
 
 package main;
 
-import ast;
+import syntax;
 
 
 fn checkname(k: nkind, want: str) void = {

lib/ww/syntax/decl.ww

@@ -1,10 +1,9 @@
-// lib/ww/parse/decl.ww — declaration parsing, split out of parse.ww.
+// lib/ww/syntax/decl.ww — declaration parsing, split out of parse.ww.
 
-package parse;
+package syntax;
 
 import os;
 import strings;
-import tok;
 
 // `import encoding.utf8;` — the driver resolves the dotted path to
 // a directory; only the leaf (`utf8`) is needed downstream as the

lib/ww/syntax/expr.ww

@@ -1,9 +1,8 @@
-// lib/ww/parse/expr.ww — expression parsing, split out of parse.ww.
+// lib/ww/syntax/expr.ww — expression parsing, split out of parse.ww.
 
-package parse;
+package syntax;
 
 import os;
-import tok;
 
 // streqlocal — str-to-str compare. Inlined here to avoid a cross-
 // module `use sym;` for one call site.

lib/ww/syntax/lex.ww

@@ -1,4 +1,4 @@
-// lib/ww/lex/lex.ww — port of cmd/wcc/lex.c.
+// lib/ww/syntax/lex.ww — port of cmd/wcc/lex.c.
 //
 // The DFA, the helpers, and the order of decisions all mirror the C
 // version exactly. The 990_selfhost test diffs the resulting token
@@ -11,10 +11,8 @@
 // in shape, not in observable behaviour. Token kind values stay
 // numerically identical.
 
-package lex;
+package syntax;
 
-// Sibling import (tok) auto-resolves via task #22 dir-enum when
-// callers `import lex;` (which dir-enums lib/ww/lex/).
 import os;
 import ascii;
 import strings;

lib/ww/syntax/parse.ww

@@ -1,4 +1,4 @@
-// lib/ww/parse/parse.ww — port of cmd/wcc/parse.c (entry + plumbing).
+// lib/ww/syntax/parse.ww — port of cmd/wcc/parse.c (entry + plumbing).
 //
 // Split into Hare-style submodule: parse.ww (here) holds the parser
 // struct, lexer plumbing, parsetype, parsefile (entry). Expression,
@@ -10,14 +10,12 @@
 // stores the current token as flat primitive fields rather than a
 // nested `tok` struct; `refill` copies a freshly lexed token in.
 
-package parse;
+package syntax;
 
-// Sibling imports (expr, stmt, decl) auto-resolve via task #22
-// dir-enum when callers `import parse;` (which dir-enums
-// lib/ww/parse/).
+// Sibling files (expr, stmt, decl) are the same `package syntax`,
+// auto-resolved via task #22 dir-enum of lib/ww/syntax/.
 import os;
 import strings;
-import tok;
 
 type parser = struct {
 	l:    *lex,

lib/ww/syntax/stmt.ww

@@ -1,9 +1,8 @@
-// lib/ww/parse/stmt.ww — statement parsing, split out of parse.ww.
+// lib/ww/syntax/stmt.ww — statement parsing, split out of parse.ww.
 
-package parse;
+package syntax;
 
 import os;
-import tok;
 
 fn parseletlocal(p: *parser) *node = {
 	let pf = p.curfile;

lib/ww/syntax/sym.ww

@@ -1,10 +1,10 @@
-// lib/ww/sym.ww — port of cmd/wcc/sym.c.
+// lib/ww/syntax/sym.ww — port of cmd/wcc/sym.c.
 //
 // Per-scope hashtable, chained to the parent. Lookup walks up.
 // Plan 9 / Hare flavoured. Duplicate definitions in the same scope
 // return nil; the caller flags the error.
 
-package ww;
+package syntax;
 
 // Symbol kinds — must stay numerically aligned with cmd/wcc/ww.h Skind.
 type skind = enum i32 {
@@ -108,11 +108,10 @@ export fn scopelookup(s: *scope, name: str) *sym = {
 // Same FNV bucket + hashnext chain + parent walk as scopelookup, with
 // an `skind == SK_TYPE` filter. Used to disambiguate the bare-TNAME
 // vs imported-module-bareword collision: when scopelookup returns the
-// SK_USE sym for a leaf that ALSO names a type (e.g. `tok` struct
-// declared in lib/ww/lex/tok.ww with `package lex;` while
-// `import tok;` registers a same-name SK_USE), the resolver needs
-// the type entry — the struct's mod may differ from the leaf (lex/tok
-// pair) so scopelookupinmodule(c, leaf, leaf) won't find it.
+// SK_USE sym for a leaf that ALSO names a type (a same-name `import X;`
+// SK_USE shadowing a struct X declared in another module), the resolver
+// needs the type entry — the struct's mod may differ from the leaf so
+// scopelookupinmodule(c, leaf, leaf) won't find it.
 //
 // #58/#50: within each scope, Pass-1 prefers an SK_TYPE whose `sym.mod`
 // matches `mod`; Pass-2 falls back to the first SK_TYPE regardless of

lib/ww/syntax/tok.ww

@@ -1,4 +1,4 @@
-// lib/ww/lex/tok.ww — port of cmd/wcc/tok.c plus the Tkind /
+// lib/ww/syntax/tok.ww — port of cmd/wcc/tok.c plus the Tkind /
 // Tok / Pos shapes from cmd/wcc/ww.h.
 //
 // Token kind values must stay numerically equal to the C side: the
@@ -9,7 +9,7 @@
 // Bottom of file: tokprint, which emits one token per line in a
 // format identical to cmd/wcc/tok.c:tokprint().
 
-package lex;
+package syntax;
 
 import os;
 import strconv;

lib/ww/syntax/toktest.ww

@@ -1,7 +1,7 @@
 // toktest — functional-equivalence pin for [[tokname]], [[kwlookup]]
 // (struct fold S1) and [[tokprint]]/fputq (struct fold S9, the
 // if-ladder → switch folds in tok.ww).
-// Run with `ww run -I lib/ww/lex lib/ww/lex/toktest.ww`.
+// Run with `ww run -I lib/ww lib/ww/syntax/toktest.ww`.
 //
 // tokname is checked against every tkind value (the full ladder the
 // switch replaced, plus the unknown-kind fallback); kwlookup is
@@ -22,8 +22,7 @@
 package main;
 
 import os;
-import tok;
-import lex;
+import syntax;
 
 
 fn checkname(k: tkind, want: str) void = {

lib/ww/syntax/typ.ww

@@ -1,4 +1,4 @@
-// lib/ww/typ.ww — port of cmd/wcc/type.c.
+// lib/ww/syntax/typ.ww — port of cmd/wcc/type.c.
 //
 // Status: full structural port. The C version uses module-globals for
 // the primitive types (tyvoid, tyi32, …); ww doesn't have writable
@@ -6,7 +6,7 @@
 // the checker passes around explicitly. typesinit fills the tctx
 // once per program.
 
-package ww;
+package syntax;
 
 import os;