hopefully last UX refinement for flasher

Author: FugLong

docs/quickstart.md

@@ -16,7 +16,7 @@ Do this on the **same computer** where you use **OpenTrack**, on your **home Wi
 1. Open **`http://azimuth.local:8080/`** in a browser.  
    If that fails, use **`http://<device-ip>:8080`** (find the device in your router’s list). The address must end in **`:8080`**.
 2. Turn **UDP to PC** **on** if it is off.
-3. In **UDP address**, enter this PC’s **IPv4** on your LAN (often something like `192.168.1.x`). If you opened the page on that PC, use any **“fill address”** or similar control the page offers.
+3. Click **Fill address** (the page fills in this PC’s address for you). If you don’t see that button, type this PC’s **IPv4** (e.g. `192.168.1.x`) in **UDP address** instead.
 4. **Scroll down** and **save**.
 
 ## 3. OpenTrack

web-flasher/index.html

@@ -231,7 +231,7 @@ <h2 id="h-after">When it’s done</h2>
     <ol class="after-steps">
       <li>On your phone or computer, connect to the <strong>Azimuth-Setup</strong> Wi‑Fi network. It appears in your Wi‑Fi list after a first-time flash when you power the board on (before home Wi‑Fi is set up).</li>
       <li>A setup page should open, or go to <code>192.168.4.1</code> in a browser. Enter your home Wi‑Fi name and password, scroll to the <strong>bottom</strong>, and <strong>save</strong> so the board can join your network.</li>
-      <li>On your home Wi‑Fi, on the <strong>same PC where you run OpenTrack</strong>, open <a class="link-main" href="http://azimuth.local:8080/">azimuth.local:8080</a>. Enter that PC’s network address in the UDP section, scroll down, and save—then use OpenTrack’s <strong>UDP</strong> input. More detail: <a href="https://github.com/FugLong/Azimuth/blob/main/docs/quickstart.md">quick start guide</a>.</li>
+      <li>On the <strong>PC where you run OpenTrack</strong> (same home Wi‑Fi), open <a class="link-main" href="http://azimuth.local:8080/">azimuth.local:8080</a>. Turn <strong>UDP to PC</strong> on, click <strong>Fill address</strong>, scroll to the bottom and save. Then open OpenTrack and pick <strong>UDP</strong> as the input. More help: <a href="https://github.com/FugLong/Azimuth/blob/main/docs/quickstart.md">quick start</a>.</li>
     </ol>
     <p class="fine-print">If <code>azimuth.local</code> doesn’t open, use the device’s IP from your router instead, still with <strong>:8080</strong> at the end.</p>
   </section>