Add CW/Morse code decoder mode

New signal mode for decoding Morse code (CW) transmissions via SDR.
Includes route blueprint, utility decoder, frontend UI, and tests.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

static/css/modes/morse.css

@@ -0,0 +1,127 @@
+/* Morse Code / CW Decoder Styles */
+
+/* Scope canvas container */
+.morse-scope-container {
+    background: var(--bg-primary);
+    border: 1px solid var(--border-color);
+    border-radius: 6px;
+    padding: 8px;
+    margin-bottom: 12px;
+}
+
+.morse-scope-container canvas {
+    width: 100%;
+    height: 120px;
+    display: block;
+    border-radius: 4px;
+}
+
+/* Decoded text panel */
+.morse-decoded-panel {
+    background: var(--bg-primary);
+    border: 1px solid var(--border-color);
+    border-radius: 6px;
+    padding: 16px;
+    min-height: 200px;
+    max-height: 400px;
+    overflow-y: auto;
+    font-family: var(--font-mono);
+    font-size: 18px;
+    line-height: 1.6;
+    color: var(--text-primary);
+    word-wrap: break-word;
+    flex: 1;
+}
+
+.morse-decoded-panel:empty::before {
+    content: 'Decoded text will appear here...';
+    color: var(--text-dim);
+    font-size: 14px;
+    font-style: italic;
+}
+
+/* Individual decoded character with fade-in */
+.morse-char {
+    display: inline;
+    animation: morseFadeIn 0.3s ease-out;
+    position: relative;
+}
+
+@keyframes morseFadeIn {
+    from {
+        opacity: 0;
+        color: var(--accent-cyan);
+    }
+    to {
+        opacity: 1;
+        color: var(--text-primary);
+    }
+}
+
+/* Small Morse notation above character */
+.morse-char-morse {
+    font-size: 9px;
+    color: var(--text-dim);
+    letter-spacing: 1px;
+    display: block;
+    line-height: 1;
+    margin-bottom: -2px;
+}
+
+/* Reference grid */
+.morse-ref-grid {
+    transition: max-height 0.3s ease, opacity 0.3s ease;
+    max-height: 500px;
+    opacity: 1;
+    overflow: hidden;
+}
+
+.morse-ref-grid.collapsed {
+    max-height: 0;
+    opacity: 0;
+}
+
+/* Toolbar: export/copy/clear */
+.morse-toolbar {
+    display: flex;
+    gap: 6px;
+    margin-bottom: 8px;
+    flex-wrap: wrap;
+}
+
+.morse-toolbar .btn {
+    font-size: 11px;
+    padding: 4px 10px;
+}
+
+/* Status bar at bottom */
+.morse-status-bar {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    font-size: 11px;
+    color: var(--text-dim);
+    padding: 6px 0;
+    border-top: 1px solid var(--border-color);
+    margin-top: 8px;
+}
+
+.morse-status-bar .status-item {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+}
+
+/* Visuals container layout */
+#morseVisuals {
+    flex-direction: column;
+    gap: 12px;
+    padding: 16px;
+    height: 100%;
+}
+
+/* Word space styling */
+.morse-word-space {
+    display: inline;
+    width: 0.5em;
+}