Add /privacy page with shared footer across non-map pages

New PrivacyLive page explains that collected/submitted data is used
only for propagation research and will never be sold, traded, or
disclosed. Layouts.app now renders a small footer with the NTMS
attribution and a Privacy link on every page that uses it, so the
full-screen map pages are untouched. The duplicate NTMS credit on
the About page is removed since it now lives in the shared footer.

lib/microwaveprop_web/components/layouts.ex

@@ -79,6 +79,20 @@ defmodule MicrowavepropWeb.Layouts do
       </div>
     </main>
 
+    <footer class="px-4 sm:px-6 lg:px-8 pb-6">
+      <div class={["mx-auto text-center text-xs opacity-60 space-y-1", @max_width]}>
+        <div>
+          Built by and for the
+          <a href="https://ntms.org" target="_blank" class="link link-hover">
+            North Texas Microwave Society
+          </a>.
+        </div>
+        <div>
+          <.link navigate="/privacy" class="link link-hover">Privacy</.link>
+        </div>
+      </div>
+    </footer>
+
     <.flash_group flash={@flash} />
     """
   end

lib/microwaveprop_web/live/about_live.ex

@@ -156,11 +156,6 @@ defmodule MicrowavepropWeb.AboutLive do
           </ul>
         </div>
 
-        <p class="text-xs opacity-60 pt-4 border-t border-base-300">
-          Built by and for the <a href="https://www.ntms.org" target="_blank" class="link link-hover">
-            North Texas Microwave Society
-          </a>.
-        </p>
       </section>
     </Layouts.app>
     """

lib/microwaveprop_web/live/privacy_live.ex

@@ -0,0 +1,91 @@
+defmodule MicrowavepropWeb.PrivacyLive do
+  @moduledoc false
+  use MicrowavepropWeb, :live_view
+
+  @impl true
+  def mount(_params, _session, socket) do
+    {:ok, assign(socket, :page_title, "Privacy")}
+  end
+
+  @impl true
+  def render(assigns) do
+    ~H"""
+    <Layouts.app flash={@flash} current_scope={@current_scope} max_width="max-w-3xl">
+      <.header>
+        Privacy
+        <:subtitle>What we collect, and what we promise to do with it.</:subtitle>
+      </.header>
+
+      <section class="space-y-6 text-sm leading-relaxed">
+        <p>
+          NTMS Propagation Prediction is an amateur-radio research project run by
+          and for the North Texas Microwave Society. Any information we collect or
+          that you submit is used exclusively to study microwave propagation and
+          improve the prediction model on this site.
+        </p>
+
+        <div class="space-y-3">
+          <h2 class="text-lg font-bold">We will never</h2>
+          <ul class="list-disc list-outside pl-5 space-y-1">
+            <li>Sell your information.</li>
+            <li>Trade or barter it to third parties.</li>
+            <li>
+              Disclose it to anyone outside the project, except where required by law.
+            </li>
+          </ul>
+        </div>
+
+        <div class="space-y-3">
+          <h2 class="text-lg font-bold">What we collect</h2>
+          <ul class="list-disc list-outside pl-5 space-y-1">
+            <li>
+              <strong>Account information</strong> — when you register, we store
+              your callsign, email address, and a hashed password. Email is only
+              used for account confirmation and password resets.
+            </li>
+            <li>
+              <strong>Submitted data</strong> — beacon listings, QSOs, and beacon
+              monitor reports you voluntarily submit. These are published back to
+              other amateurs as part of the project.
+            </li>
+            <li>
+              <strong>Approximate location</strong> — our CDN (Cloudflare) provides
+              a rough latitude/longitude derived from your IP so the map can open
+              centered near you. It is not stored with your account or any
+              submission.
+            </li>
+            <li>
+              <strong>Basic request logs</strong> — standard web server logs
+              (timestamp, path, status, user agent) retained for a short period
+              for debugging and abuse prevention.
+            </li>
+          </ul>
+        </div>
+
+        <div class="space-y-3">
+          <h2 class="text-lg font-bold">How it's used</h2>
+          <p>
+            Everything feeds one goal: calibrating and improving propagation
+            predictions for the amateur microwave bands. Aggregate or anonymized
+            results may appear in publications, talks, or on this site, but
+            individual personal details (email, password, IP) will never be
+            published.
+          </p>
+        </div>
+
+        <div class="space-y-3">
+          <h2 class="text-lg font-bold">Questions or removal requests</h2>
+          <p>
+            If you'd like your account deleted or your submissions removed,
+            contact the
+            <a href="https://ntms.org" target="_blank" class="link link-hover">
+              North Texas Microwave Society
+            </a>
+            and we'll take care of it.
+          </p>
+        </div>
+      </section>
+    </Layouts.app>
+    """
+  end
+end

lib/microwaveprop_web/router.ex

@@ -76,6 +76,7 @@ defmodule MicrowavepropWeb.Router do
       live "/rover", RoverLive
       live "/algo", AlgoLive
       live "/about", AboutLive
+      live "/privacy", PrivacyLive
 
       # Beacons: public read + submit (pending admin approval)
       live "/beacons", BeaconLive.Index, :index