fix(send/receive): unify card width, justify receive footer, fix recipient-row button height/clip/glyph

Send and Receive are now consistent in layout, and the Send recipient row's buttons
render correctly.

Card envelope (Send ⇄ Receive consistency):
- Add Layout::mainComposeCardBox(availW) — a single shared source for the compose card's
  width + centering (fill the available column up to content-max-width, then center). Both
  tabs derive their card from it, so they can't drift again. Previously Send capped at
  760dp and Receive at 860dp, so the Send card rendered ~150px narrower on any window wider
  than ~860dp; now they fill available width identically.

Receive:
- Justify the footer buttons edge-to-edge (equal shares over the live count) instead of
  left-clustering with dead space, matching Send's full-width footer rhythm.
- Build the address-dropdown preview to the combo's real pixel width so the trailing
  balance ("— 12.00000000 DRGX") no longer hard-clips at 150% (was char-count truncation).

Send recipient row (input | Paste | contacts-icon):
- Pin the contacts icon button to the frame height so the larger iconMed font doesn't
  auto-size it taller than Paste/the input.
- Reserve the real ItemSpacing.x gaps (not the smaller spacingSm token) so the row no
  longer overshoots the card and clips the icon's right border.

draw_helpers (root cause, app-wide):
- TactileButton's icon path measured/drew the label INCLUDING the "##id" suffix (which
  CalcTextSizeA/AddText don't strip the way ImGui's text render does), shoving the glyph
  off-center-left. Strip at "##" before measuring/drawing. Corrects any icon button that
  passes an explicit size and a "##id" label; no-op for labels without "##".

Verified via headless sweeps at 1.0x and 1.5x, plus a real 3800px-wide render (both cards
byte-identical at L=1174/R=2773). ctest 1/1.

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

src/ui/layout.h

@@ -179,6 +179,17 @@ inline float kSidePanelWidthRatio() { return schema::UI().drawElement("panels",
 // [layout] content-max-width; default is generous so data-dense screens stay comfortable.
 inline float kContentMaxWidth() { return schema::UI().drawElement("layout", "content-max-width").sizeOr(1600.0f) * dpiScale(); }
 
+// Shared compose-card envelope for the Send + Receive tabs (and any tab wanting the same box): fill the
+// available column up to the content-max-width cap, then center the leftover as margin. Both tabs MUST
+// derive their card width/offset from this so the two envelopes stay byte-for-byte identical — they
+// previously drifted (Send capped at 760dp, Receive at 860dp), so the Send card rendered narrower than
+// Receive on any window wider than ~860dp. Returns {width, offsetX} in the same units as availW.
+struct CardBox { float width; float offsetX; };
+inline CardBox mainComposeCardBox(float availW) {
+    float w = std::min(availW, kContentMaxWidth());
+    return CardBox{ w, std::max(0.0f, (availW - w) * 0.5f) };
+}
+
 inline float kTableMinHeight()   { return schema::UI().drawElement("panels", "table").getFloat("min-height", 150.0f) * dpiScale(); }
 inline float kTableHeightRatio() { return schema::UI().drawElement("panels", "table").getFloat("height-ratio", 0.45f); }