Review fixes #2: bigger flag star, TG header below nav, board-tile relocation

Addressing the review on #23:
- Flag star scaled up ~25% (the hammer&sickle emblem unchanged, kept clear of it).
- TG fullscreen header: drop the WHOLE header below the content-safe-area top
  inset (the hamburger stays to the right of the title), instead of pinning the
  hamburger to the physical top edge.
- DnD: a placed (pending) tile can now be relocated by dragging it to another
  board cell (board->board); it lifts off its source cell while dragged; and it
  can be grabbed even on the zoomed board (touch-action:none on the pending
  cell, so the drag wins over the board pan). The manual-selection blue frame
  now clears on recall.

ui/src/game/Board.svelte

@@ -277,6 +277,9 @@
   }
   .cell.pending {
     background: var(--tile-pending);
+    /* The placed tile owns the pointer so it can be dragged to relocate it (even on the zoomed
+       board) instead of the touch starting a board pan (Stage 17). */
+    touch-action: none;
   }
   /* Lines-off variant: a gapless checkerboard. The 1px grid gaps (and the cell-line they
      reveal) collapse, saving ~14px of board width; plain cells alternate shades, and tiles