Add pedigree lookup and ancestry tree page

New 🌳 Pedigree view: enter a dog's ISO chip or SKK registration number
and see its ancestry rendered as a tree. SKK has no public API, so the
server drives SKK Hunddata like a browser: it resolves the input to an
internal hundid via the Hund_sok.aspx/HundData page-method, renders 7
generations per pedigree page, parses the rowspan grid into ahnentafel
positions, and follows each generation's leaves deeper by reading their
hundid out of the __doPostBack response viewstate.

A lookup returns the first 7 generations immediately and crawls deeper in
the background; the client polls and fills the tree in as ancestors
arrive. Finished trees are cached per dog in a new pedigree_cache table
(pedigrees don't change), so a dog is crawled once and repeats are instant.
The endpoints sit behind auth like the rest of /api/*, and the crawl is
kept polite (warmed session, delay between requests, one coalesced job per
dog, hard caps).

src/index.html

@@ -70,6 +70,7 @@
         <div id="puppy-age" class="puppy-age" hidden></div>
       </div>
       <div class="header-actions">
+        <button type="button" id="pedigree-btn" class="ghost icon-btn" aria-label="Pedigree" title="Pedigree">🌳</button>
         <button type="button" id="settings-btn" class="ghost icon-btn" aria-label="Settings" title="Settings">⚙️</button>
         <button type="button" id="logout-btn" class="ghost icon-btn" aria-label="Log out" title="Log out">🚪</button>
         <div id="online-status" class="status-pill"></div>
@@ -272,6 +273,32 @@
     </footer>
     </div><!-- /#app -->
 
+    <!-- Pedigree lookup. A distinct full-screen view (hides #app while open)
+         that resolves a dog by chip / registration number / name against SKK
+         and renders its ancestry as a tree. Online-only. -->
+    <div id="pedigree-screen" class="pedigree-screen" hidden>
+      <header class="pedigree-header">
+        <button type="button" id="pedigree-back" class="ghost icon-btn" aria-label="Back to tracker" title="Back">←</button>
+        <h1>🌳 Pedigree</h1>
+      </header>
+      <main class="pedigree-main">
+        <form id="pedigree-form" class="pedigree-form">
+          <input type="text" id="pedigree-q" autocomplete="off" spellcheck="false"
+                 placeholder="Chip or registration number" aria-label="Dog chip or registration number" />
+          <button type="submit" id="pedigree-lookup">Look up</button>
+        </form>
+        <p class="muted-note pedigree-hint">
+          Looks up a dog in <strong>SKK Hunddata</strong> by ISO chip number
+          (e.g. 752095600044144) or registration number (e.g. SE23536/2026),
+          then traces its ancestry. Needs an internet connection.
+        </p>
+        <p id="pedigree-status" class="pedigree-status" hidden></p>
+        <div id="pedigree-choose" class="pedigree-choose" hidden></div>
+        <div id="pedigree-subject" class="pedigree-subject" hidden></div>
+        <div id="pedigree-tree" class="pedigree-tree"></div>
+      </main>
+    </div><!-- /#pedigree-screen -->
+
     <dialog id="changelog-dialog">
       <form method="dialog" id="changelog-form">
         <h3>Changelog</h3>