refactor(ui): extract shared ProgressBar / CopyableTextOverlay / DrawPill helpers

UI-standardization audit: three draw patterns were copy-pasted across tabs and
dialogs. Promote each to a material:: helper and adopt at every verbatim site.
Output is pixel-identical (same colors/geometry threaded through as params).

- material::DrawProgressBar / ProgressBar — replaces 3 byte-identical rounded
  fill bars in the daemon/xmrig/bootstrap download dialogs.
- material::CopyableTextOverlay — the click-to-copy affordance (hit button +
  hand cursor + tooltip + hover underline + clipboard) shared by the peers
  best-block hash and the 3 mining stats (difficulty/block/address). Returns
  "copied this frame" so callers keep their own toast (no ui-layer dependency).
- material::DrawPill / PillSize — rounded bg + optional border + inset text
  badge, shared by the explorer status pill, the market Z/T chip, and the
  network official/custom tag.

Divergent one-offs left in place (transactions status pills use schema rounding
around pre-positioned multi-line text; the mining filter-pill is a button bg).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/network_tab.cpp

@@ -285,9 +285,8 @@ void RenderLiteNetworkTab(App* app)
         ImVec2 tagSz = cap->CalcTextSizeA(cap->LegacySize, FLT_MAX, 0, tag);
         float tagX = rx - tagSz.x;
         float tagY = cardMin.y + 9.0f * dp;
-        dl->AddRectFilled(ImVec2(tagX - 6 * dp, tagY - 1 * dp), ImVec2(rx + 6 * dp, tagY + tagSz.y + 1 * dp),
-                          tagBg, 4.0f * dp);
-        dl->AddText(cap, cap->LegacySize, ImVec2(tagX, tagY), tagFg, tag);
+        material::DrawPill(dl, ImVec2(tagX - 6 * dp, tagY - 1 * dp), tag, cap, tagFg, tagBg, 0,
+                           ImVec2(6 * dp, 1 * dp), 4.0f * dp);
         if (selected) {
             const char* inUse = TR("lite_net_in_use");
             ImVec2 uSz = cap->CalcTextSizeA(cap->LegacySize, FLT_MAX, 0, inUse);