Tiles resize from anywhere, so nothing marks the spots

Every edge and both bottom corners resize now, so the little marks that used
to appear on hover were pointing at the whole rim. They are gone — corners,
edges and the seam pill alike — and the cursor over an edge is what says it
can be dragged, the way a window's own edges do it. The seam still shows
itself while it is actually being dragged, which says what is moving rather
than where you may push.

With nothing drawn, the grips could be made to cover the rim properly: the
top strip now runs corner to corner instead of stopping 24px short, the
sides run from it down to the bottom corners, and the bottom strip fills
between those. No dead spots left along an edge.

The side grips also stopped standing down at a seam. They only did so to
avoid stacking three marks in one place, and it cost real ground: a tile
taller than its neighbour lost its whole side, not just the part the seam
covers. The seam sits above them anyway, so it still wins where it exists
and the rest of the edge now works.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -189,16 +189,17 @@ below. Nothing is installed without someone clicking.
 
 - **＋** — add any enabled module; multiple tiles of the same module are
   fine (e.g. two transcripts filtered to different channels).
-- Drag a tile by its **title bar** to move it; drag either **bottom
-  corner** to resize; **✕** removes it. Hover a tile and a small mark
-  appears on each **edge** — drag one to move just that edge, so the tile
-  grows or shrinks into the space beside it while the opposite edge stays
-  put. The bottom edge is the exception: when another tile sits directly
-  below, it moves the shared edge instead, trading rows between the two so
-  the column keeps its total height. Tiles sit flush — when two share a
-  vertical edge, hover the seam and a pill appears; drag it to trade width
-  (macOS split-view style). That seam belongs to the pill, so the two tiles'
-  own side marks step aside there.
+- Drag a tile by its **title bar** to move it; **✕** removes it.
+- **Resize from any edge or bottom corner**, the way a window resizes:
+  nothing is drawn on a tile to mark the spots — the cursor over an edge is
+  what says it can be dragged. An edge moves only itself, so the tile grows
+  or shrinks into the space beside it while the opposite edge stays put,
+  stopping at a neighbour or at the module's own minimum size. Two
+  exceptions, both of which move a *shared* edge instead: with another tile
+  directly below, the bottom edge trades rows between the two so the column
+  keeps its total height; and where two tiles meet side by side, the seam
+  between them trades width (macOS split-view style), showing itself only
+  while you drag it.
 - **Fullscreen** (the ⛶ button) is a viewing mode: the menu bar hides (its
   green lip at the top-left brings it back, minus the Admin button), the
   occupied columns stretch to the full width, and every column runs to the