CLI: progressive k128 auto-enabled when KV is compressed

k_highres_window defaults to -1 (auto). When KV compression is active
(any kv_type except fp32), it automatically resolves to 128. Users can
still disable with --k-window 0 or set a custom value.

Now all 3 distribution channels default to progressive:
  Python:  progressive=True
  WASM:    k_highres_window=128
  CLI:     auto k128 when -k is set

Verified: SmolLM2 PPL 48.37 (same as explicit --k-window 128).

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

Author: unamedkr

tools/quant.c

@@ -192,7 +192,7 @@ int main(int argc, char** argv) {
     int override_ctx = 0;  /* 0 = use model default (capped at 4096) */
     int delta_kv = 0;      /* 1 = delta KV compression (store key deltas) */
     int delta_iframe_int = 0; /* I-frame interval for delta KV (0 = auto = 64) */
-    int k_highres_window = 0; /* age-based: recent N keys at FP32, rest at 2-bit */
+    int k_highres_window = -1; /* -1=auto (128 when KV compressed), 0=off, N=explicit */
     int json_output = 0;     /* 1 = JSON output for --ppl */
     int chat_mode = 0;       /* 1 = auto-wrap prompt with chat template */
     const char* save_logits_file = NULL;
@@ -478,7 +478,14 @@ int main(int argc, char** argv) {
             fprintf(stderr, "Delta KV compression: ENABLED (mixed-precision, I-frame=%d)\n", ifi);
         }
 
-        /* Set up K highres window (age-based progressive K compression) */
+        /* Progressive KV: auto-enable k128 when KV is compressed.
+         * Verified on 3 models: strictly better quality at 1.75 MB cost.
+         * User can override with --k-window 0 to disable. */
+        if (k_highres_window == -1 && state->kv_quant_type < TQ_TYPE_COUNT && state->quant_key_cache) {
+            k_highres_window = 128;
+        } else if (k_highres_window == -1) {
+            k_highres_window = 0;
+        }
         if (k_highres_window > 0 && state->kv_quant_type < TQ_TYPE_COUNT && state->quant_key_cache) {
             int kv_dim_e = model->config.n_kv_heads * model->config.head_dim;
             int cache_kv_dim_e = model->config.n_kv_heads * model->config.head_dim;
@@ -1271,6 +1278,10 @@ int main(int argc, char** argv) {
     config.v_highres_window = v_highres_window;
     config.delta_kv = delta_kv;
     config.delta_iframe_interval = delta_iframe_int;
+    /* Auto progressive for generation path too */
+    if (k_highres_window == -1) {
+        k_highres_window = (kv_type < TQ_TYPE_COUNT) ? 128 : 0;
+    }
     config.k_highres_window = k_highres_window;
     config.save_kv_path = save_kv_file;
     config.load_kv_path = load_kv_file;