Move to single click audio chat UX on Obsidian client

- Capabillity
  New default UX has 1 long-press to send transcribed audio message

  - Removes the previous default of 3 clicks required to send audio message
    - The record > stop > send process to send audio messages was unclear
  - Still allows stopping message from being sent, if users want to make
    correction to transcribed audio
  - Removes inadvertent long audio transcriptions if user forgets to
    press stop when recording

- Changes
  - Record audio while microphone button pressed
  - Show auto-send 3s countdown timer UI for audio chat message
    Provide a visual cue around send button for how long before audio
    message is automatically sent to Khoj for response
  - Auto-send msg in 3s unless stop send message button clicked

src/interface/obsidian/styles.css

@@ -254,11 +254,35 @@ img {
     height: 32px;
     width: 32px;
 }
-#khoj-chat-send .svg-icon {
+
+#khoj-chat-send {
+    padding: 0;
+    position: relative;
+}
+#khoj-chat-send .lucide-arrow-up-circle {
     background: var(--khoj-sun);
     border-radius: 50%;
     color: #222;
 }
+#khoj-chat-send .lucide-stop-circle {
+    transform: rotateY(-180deg) rotateZ(-90deg);
+}
+#khoj-chat-send .lucide-stop-circle circle {
+    stroke-dasharray: 62px;  /* The circumference of the circle with 7px radius */
+    stroke-dashoffset: 0px;
+    stroke-linecap: round;
+    stroke-width: 2px;
+    stroke: var(--main-text-color);
+    fill: none;
+}
+@keyframes countdown {
+    from {
+        stroke-dashoffset: 0px;
+    }
+    to {
+        stroke-dashoffset: -62px;  /* The circumference of the circle with 7px radius */
+    }
+}
 
 @media (pointer: coarse), (hover: none) {
     #khoj-chat-body.abbr[title] {