feat(addresses): improve address labeling and view-only handling

- Add expanded address icon picker with search, bottom-aligned actions, and improved modal sizing
- Embed a pickaxe icon font subset and wire it into typography/address icon rendering
- Track view-only shielded addresses and prevent sends from non-spendable z-addresses
- Improve address transfer dialog sizing, max amount handling, and text clipping
- Tune main header layout values in ui.toml
- Update README, codebase overview, and third-party license documentation

src/ui/material/typography.h

@@ -175,6 +175,14 @@ public:
     ImFont* iconMed()   const { return iconFonts_[1] ? iconFonts_[1] : getFont(TypeStyle::Body1); }
     ImFont* iconLarge() const { return iconFonts_[2] ? iconFonts_[2] : getFont(TypeStyle::H5); }
     ImFont* iconXL()    const { return iconFonts_[3] ? iconFonts_[3] : getFont(TypeStyle::H3); }
+    ImFont* pickaxeSmall() const { return pickaxeFonts_[0] ? pickaxeFonts_[0] : iconSmall(); }
+    ImFont* pickaxeMed()   const { return pickaxeFonts_[1] ? pickaxeFonts_[1] : iconMed(); }
+    ImFont* pickaxeLarge() const { return pickaxeFonts_[2] ? pickaxeFonts_[2] : iconLarge(); }
+    ImFont* pickaxeXL()    const { return pickaxeFonts_[3] ? pickaxeFonts_[3] : iconXL(); }
+
+    ImFont* pickaxeFontForSize(float size) const;
+
+    static constexpr ImWchar kPickaxeCodepoint = 0xE001;
 
     /**
      * @brief Resolve a font name string to ImFont*
@@ -254,10 +262,12 @@ private:
     
     // Icon fonts at different sizes: [0]=small(14), [1]=med(18), [2]=large(24), [3]=xl(40)
     ImFont* iconFonts_[4] = {};
+    ImFont* pickaxeFonts_[4] = {};
     static constexpr int kNumIconSizes = 4;
     
     // Load an icon-only font at a specific pixel size
     ImFont* loadIconFont(ImGuiIO& io, float size, const char* name);
+    ImFont* loadPickaxeFont(ImGuiIO& io, float size, const char* name);
     
     // Type specifications
     static const TypeSpec* getTypeSpecs();