fix: chat input correctness and mobile UX

- after-request → after-settle: scrollChat() was firing before HTMX
  swapped the new message into the DOM, so the chat log didn't scroll
  to the new message. after-settle fires post-swap, post-settle.

- hx-sync="this:drop": prevents duplicate submissions if the user taps
  SEND a second time while a slow Ollama response is in flight.

- hx-disabled-elt="find button": disables SEND button visually during
  a pending request; paired with hx-sync for belt-and-suspenders.

- autocorrect="off" autocapitalize="none" spellcheck="false": iOS
  autocorrect mangles model names (llama3.2 etc.) and autocapitalize
  uppercases every message's first word. Both are wrong for a terminal-
  style chat interface.

- enterkeyhint="send": tells the iOS/Android soft keyboard to label
  the Return key "Send" instead of the generic return arrow.

https://claude.ai/code/session_01M4L3R98N5fgXFZRvV8X9b6

src/dashboard/templates/index.html

@@ -55,12 +55,18 @@
           hx-target="#chat-log"
           hx-swap="beforeend"
           hx-indicator="#send-indicator"
-          hx-on::after-request="this.reset(); scrollChat()"
+          hx-sync="this:drop"
+          hx-disabled-elt="find button"
+          hx-on::after-settle="this.reset(); scrollChat()"
           style="display:flex; flex:1; gap:8px;">
       <input type="text"
              name="message"
              placeholder="send a message to timmy..."
              autocomplete="off"
+             autocorrect="off"
+             autocapitalize="none"
+             spellcheck="false"
+             enterkeyhint="send"
              required />
       <button type="submit">
         SEND