Phase 7a: bitwise operators & | ^ << >> ~ (retire band/bor/shl/…)

First step of the "stop feeling like C" pass. Bitwise ops were functions
(`band(x, MASK)`, `shl(a, 3)`); they are now real operators:

  band -> &   bor -> |   bxor -> ^   shl -> <<   shr -> >>   bnot -> ~

Precedence is Go-style so the C footgun is gone: `<<`/`>>`/`&` bind like `*`,
`|`/`^` like `+`, both tighter than comparison — `flags & MASK == 0` parses as
`(flags & MASK) == 0`. `>>` is logical (lshr), matching the old `shr`.

Mechanics: lexer tokenizes `<< >> & | ^ ~`; p_mul takes `<< >> &`, p_add takes
`| ^`, p_unary takes `~`; emit_bin routes them through the existing int arith
path (arith_code gains and/or/xor/shl/lshr) and E_UN handles `~`. The six
intrinsics are deleted.

Delivered as two reseeds: (A) add the operators keeping the intrinsics, (B)
migrate every call site to operator form (85 lines across compiler + runtime,
via a balanced-paren call->operator script; two multi-line big-endian reads in
image/truetype done by hand) and delete the intrinsics. Vocabulary drops the six
from LUDIC_INTRINSICS (ludic_syntax.h, grammar, LudicTokens.kt) and the grammar
gains a bitwise-operator rule. LANGUAGE.md precedence table rewritten.

Reseeded (21724 lines); C-free fixpoint holds; goldens byte-identical (the PNG
and TrueType decoders lean on these ops); 17/17; vocab + doc-fences clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

runtime/native/core.ludic

@@ -197,11 +197,11 @@ fn rt_seed(s: int) -> void {
 # masked off only when a caller asks for a number.
 fn rt_next_rand() -> int {
   var x = rt_rng
-  x = bxor(x, shl(x, 13))
-  x = bxor(x, shr(x, 17))
-  x = bxor(x, shl(x, 5))
+  x = (x ^ (x << 13))
+  x = (x ^ (x >> 17))
+  x = (x ^ (x << 5))
   rt_rng = x
-  return band(x, 2147483647)
+  return (x & 2147483647)
 }
 
 fn rt_rng_range(lo: int, hi: int) -> int {