chore: archive QuickNav and ZTools into reference folder (#345)

Copy QuickNav and ZTools source trees into reference/ for developer
reference during the UI/UX rework. These are plain directories (not
submodules) and are not included in the build.

- reference/quicknav/ — QuickNav addon source
- reference/ztools/ — ZTools addon source

Part of the UI/UX rework preparation. See #346.

reference/ztools/package.xml

@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
+<package format="1" xmlns="https://wiki.freecad.org/Package_Metadata">
+
+  <name>ZTools</name>
+
+  <description>Extended PartDesign workbench with velocity-focused tools and advanced datum creation.</description>
+
+  <version>0.1.0</version>
+
+  <date>2026-01-24</date>
+
+  <license file="LICENSE">LGPL-3.0-or-later</license>
+
+  <content>
+    <workbench>
+      <name>ZTools</name>
+      <classname>ZToolsWorkbench</classname>
+      <subdirectory>./ztools</subdirectory>
+    </workbench>
+  </content>
+
+  <!-- Kindred Create extensions -->
+  <kindred>
+    <min_create_version>0.1.0</min_create_version>
+    <load_priority>50</load_priority>
+    <pure_python>true</pure_python>
+    <dependencies>
+      <dependency>sdk</dependency>
+    </dependencies>
+    <contexts>
+      <context id="partdesign.body" action="inject"/>
+      <context id="partdesign.feature" action="inject"/>
+    </contexts>
+  </kindred>
+
+</package>