Fix Windows MSVC build: hoist CB*_I8_RECIP out of __ARM_NEON guard (#17)

Round 11 introduced three int8 codebook reciprocal constants
(CB3_I8_RECIP, CB_I8_RECIP, CB5_I8_RECIP) inside #ifdef __ARM_NEON
blocks, but the per_block_scale computation that uses them lives
*outside* the guard and runs on every platform. NEON builds happened
to compile; MSVC x64 errored with C2065 undeclared identifier on
tq_turbo_kv.c lines 365, 585, 1324.

These are plain `static const float`s, not NEON-typed — hoist them
out of the guards so all platforms see the declarations. No
behavior change.

Fixes 8 consecutive Windows CI failures since Round 10.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: unamedkr

src/core/tq_turbo_kv.c

@@ -339,10 +339,11 @@ void tq_turbo_kv_3b_attention_ref(const float* query, const void* kv_cache,
      * 3-bit codebook has 8 entries which fit in 8 bytes — store in lower half
      * of a 16-byte register. Indices in 0-7. */
     const float* cb = tq_codebook_centroids(3);
+    /* Used by both NEON and scalar paths — keep outside the NEON guard. */
+    static const float CB3_I8_RECIP = 2.1520f / 127.0f;
 #ifdef __ARM_NEON
     static int8_t s_cb3_i8[16] = {0};
     static int s_cb3_i8_init = 0;
-    static const float CB3_I8_RECIP = 2.1520f / 127.0f;
     if (!s_cb3_i8_init) {
         for (int j = 0; j < 8; j++) {
             float v = cb[j] * (127.0f / 2.1520f);
@@ -559,11 +560,12 @@ void tq_turbo_kv_4b_attention_ref(const float* query, const void* kv_cache,
      * scale gives 16-element processing per ~10 NEON instructions vs
      * the previous ~32 scalar instructions.
      */
+    /* Used by both NEON and scalar paths — keep outside the NEON guard. */
+    static const float CB_I8_RECIP = 2.7326f / 127.0f; /* fp32 = int8 * recip */
 #ifdef __ARM_NEON
     /* Static int8 codebook (computed once at startup; safe across blocks) */
     static int8_t s_cb_i8[16] = {0};
     static int s_cb_i8_init = 0;
-    static const float CB_I8_RECIP = 2.7326f / 127.0f; /* fp32 = int8 * recip */
     if (!s_cb_i8_init) {
         for (int j = 0; j < 16; j++) {
             float v = cb[j] * (127.0f / 2.7326f);
@@ -1299,10 +1301,11 @@ void tq_turbo_kv_5b_attention_ref(const float* query, const void* kv_cache,
      * within regression test thresholds).
      */
     const float* cb = tq_codebook_centroids(5);
+    /* Used by both NEON and scalar paths — keep outside the NEON guard. */
+    static const float CB5_I8_RECIP = 1.9956f / 127.0f; /* 5-bit max centroid */
 #ifdef __ARM_NEON
     static int8_t s_cb5_i8[32] = {0};
     static int s_cb5_i8_init = 0;
-    static const float CB5_I8_RECIP = 1.9956f / 127.0f; /* 5-bit max centroid */
     if (!s_cb5_i8_init) {
         for (int j = 0; j < 32; j++) {
             float v = cb[j] * (127.0f / 1.9956f);