[fix](trx-frontend-http): fix waterfall freeze, RDS bandwidth, add jog multiplier

Fix waterfall overview freezing at steady state by tracking a monotonic
push counter instead of row array length — the array size stays constant
once the waterfall is full, so the previous row-count comparison never
triggered the incremental draw path.

Fix WFM RDS not decoding when switching to WFM from a narrowband mode:
set_mode now resets audio_bandwidth_hz to the mode-appropriate default
(180 kHz for WFM) before rebuilding the FIR, preventing the 57 kHz RDS
subcarrier from being filtered out.

Add 1×/10×/100× multiplier button group next to the jog unit selector.
jogUnit × jogMult gives the effective jog step; both are persisted to
localStorage independently.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -343,6 +343,38 @@ button:disabled { opacity: 0.6; cursor: not-allowed; }
   display: flex;
   justify-content: flex-end;
 }
+.mult-col {
+  flex: 0 0 auto;
+}
+.mult-col .label {
+  display: flex;
+  justify-content: flex-end;
+}
+.jog-mult {
+  display: flex;
+  border: 1px solid var(--border-light);
+  border-radius: 6px;
+  overflow: hidden;
+  height: 3.35rem;
+  flex-shrink: 0;
+}
+.jog-mult button {
+  border: none;
+  border-right: 1px solid var(--border-light);
+  border-radius: 0;
+  height: 100%;
+  padding: 0 0.5rem;
+  font-size: 0.85rem;
+  background: var(--input-bg);
+  color: var(--text-muted);
+  cursor: pointer;
+}
+.jog-mult button:last-child { border-right: none; }
+.jog-mult button.active {
+  background: var(--btn-bg);
+  color: var(--accent-green);
+  font-weight: 600;
+}
 .label-below-row {
   display: flex;
   flex-direction: column;