lib/ww/lex + w6a/parse: amalloc β grow → alloc([], n)! (β-1)

Phase 0 first β-batch. 4 amalloc sites across 2 β grow loops:
 - lib/ww/lex/lex.ww:570,592 lexstr string-literal escape buf
 - selfhost/cmd/w6a/parse.ww:513,548 DATA "..." escape-payload buf

Both follow the established α-per-alloc shape with loop logic left
manual: `*u8 = amalloc(_, cap): *u8` → `[]u8 = alloc([], cap)!`,
inner copy `nb[i] = old[i]` unchanged (slice indexing emits identical
asm to *u8 indexing — no .len bounds compare), `.ptr` extracted at
the *u8 consumer (s.ptr, pr.bytes). Bear-trap N/A — byte count tracked
in locals (nb, blen), slice .len = 0 never read.

Verified 132/132 + 995_self_rebuild byte-identity.

lib/ww/lex/lex.ww

@@ -567,7 +567,7 @@ fn lexident(l: *lex, start: *pos, out: *tok) void = {
 fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 	let cap: u64 = 32u64;
 	let nb:  u64 = 0u64;
-	let buf: *u8 = amalloc(l.a, cap): *u8;
+	let buf: []u8 = alloc([], cap)!;
 	for (true) {
 		let c: i32 = lpeek(l, 0u64);
 		if (c < 0) {
@@ -589,7 +589,7 @@ fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 		};
 		if (nb + 1u64 >= cap) {
 			let ncap: u64 = cap * 2u64;
-			let nb2: *u8 = amalloc(l.a, ncap): *u8;
+			let nb2: []u8 = alloc([], ncap)!;
 			let i: u64 = 0u64;
 			for (i < nb) {
 				let ix: i32 = i: i32;
@@ -608,7 +608,7 @@ fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 	out.line = start.line;
 	out.col  = start.col;
 	let s: str;
-	s.ptr = buf;
+	s.ptr = buf.ptr;
 	s.len = nb: i32;
 	out.text = s;
 };

selfhost/cmd/w6a/main.combined.ww

@@ -1662,7 +1662,7 @@ export fn parse(a: *asm_) i32 = {
 			// Parse escape sequence into a fresh growable buffer.
 			let cap: u64 = 32u64;
 			let blen: u64 = 0u64;
-			let dbuf: *u8 = amalloc(a.a, cap): *u8;
+			let dbuf: []u8 = alloc([], cap)!;
 			for (p2 < n) {
 				if (line[p2] == 34u8) { p2 = p2; p2 += 0u64; p2 = n + 1u64; }
 				else {
@@ -1697,7 +1697,7 @@ export fn parse(a: *asm_) i32 = {
 					};
 					if (blen + 1u64 > cap) {
 						let ncap: u64 = cap * 2u64;
-						let nb: *u8 = amalloc(a.a, ncap): *u8;
+						let nb: []u8 = alloc([], ncap)!;
 						let bi: u64 = 0u64;
 						for (bi < blen) { nb[bi] = dbuf[bi]; bi += 1u64; };
 						dbuf = nb;
@@ -1707,7 +1707,7 @@ export fn parse(a: *asm_) i32 = {
 					blen += 1u64;
 				};
 			};
-			pr.bytes = dbuf;
+			pr.bytes = dbuf.ptr;
 			pr.nbytes = blen;
 			a.line += 1; continue;
 		};

selfhost/cmd/w6a/parse.ww

@@ -510,7 +510,7 @@ export fn parse(a: *asm_) i32 = {
 			// Parse escape sequence into a fresh growable buffer.
 			let cap: u64 = 32u64;
 			let blen: u64 = 0u64;
-			let dbuf: *u8 = amalloc(a.a, cap): *u8;
+			let dbuf: []u8 = alloc([], cap)!;
 			for (p2 < n) {
 				if (line[p2] == 34u8) { p2 = p2; p2 += 0u64; p2 = n + 1u64; }
 				else {
@@ -545,7 +545,7 @@ export fn parse(a: *asm_) i32 = {
 					};
 					if (blen + 1u64 > cap) {
 						let ncap: u64 = cap * 2u64;
-						let nb: *u8 = amalloc(a.a, ncap): *u8;
+						let nb: []u8 = alloc([], ncap)!;
 						let bi: u64 = 0u64;
 						for (bi < blen) { nb[bi] = dbuf[bi]; bi += 1u64; };
 						dbuf = nb;
@@ -555,7 +555,7 @@ export fn parse(a: *asm_) i32 = {
 					blen += 1u64;
 				};
 			};
-			pr.bytes = dbuf;
+			pr.bytes = dbuf.ptr;
 			pr.nbytes = blen;
 			a.line += 1; continue;
 		};

selfhost/cmd/w6c/main.combined.ww

@@ -4279,7 +4279,7 @@ fn lexident(l: *lex, start: *pos, out: *tok) void = {
 fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 	let cap: u64 = 32u64;
 	let nb:  u64 = 0u64;
-	let buf: *u8 = amalloc(l.a, cap): *u8;
+	let buf: []u8 = alloc([], cap)!;
 	for (true) {
 		let c: i32 = lpeek(l, 0u64);
 		if (c < 0) {
@@ -4301,7 +4301,7 @@ fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 		};
 		if (nb + 1u64 >= cap) {
 			let ncap: u64 = cap * 2u64;
-			let nb2: *u8 = amalloc(l.a, ncap): *u8;
+			let nb2: []u8 = alloc([], ncap)!;
 			let i: u64 = 0u64;
 			for (i < nb) {
 				let ix: i32 = i: i32;
@@ -4320,7 +4320,7 @@ fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 	out.line = start.line;
 	out.col  = start.col;
 	let s: str;
-	s.ptr = buf;
+	s.ptr = buf.ptr;
 	s.len = nb: i32;
 	out.text = s;
 };

selfhost/cmd/wwdump/main.combined.ww

@@ -4279,7 +4279,7 @@ fn lexident(l: *lex, start: *pos, out: *tok) void = {
 fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 	let cap: u64 = 32u64;
 	let nb:  u64 = 0u64;
-	let buf: *u8 = amalloc(l.a, cap): *u8;
+	let buf: []u8 = alloc([], cap)!;
 	for (true) {
 		let c: i32 = lpeek(l, 0u64);
 		if (c < 0) {
@@ -4301,7 +4301,7 @@ fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 		};
 		if (nb + 1u64 >= cap) {
 			let ncap: u64 = cap * 2u64;
-			let nb2: *u8 = amalloc(l.a, ncap): *u8;
+			let nb2: []u8 = alloc([], ncap)!;
 			let i: u64 = 0u64;
 			for (i < nb) {
 				let ix: i32 = i: i32;
@@ -4320,7 +4320,7 @@ fn lexstr(l: *lex, start: *pos, out: *tok) void = {
 	out.line = start.line;
 	out.col  = start.col;
 	let s: str;
-	s.ptr = buf;
+	s.ptr = buf.ptr;
 	s.len = nb: i32;
 	out.text = s;
 };