fix(web): PDF adjust — remove the leftover line-band filter from the endpoint drag

The "full 2D" commit (5a0d9e0) added the tip aim but never removed the
y-band candidate filter from pdfAdjustHandleMove — vertical handle
drags still snapped to the boundary rect's own line, so up/down
movement was impossible (the user's original report). With the filter
gone: the end handle drags down a line and the extent extends with
clean text — verified with real touch on the emulator (down one line,
release, PUT applied: 6 per-line rects).

web/src/reader/reader.ts

@@ -1855,27 +1855,22 @@ document.addEventListener("alpine:init", () => {
       if (!ctx) return;
       const map = this.pdfPageMapping(ctx.index);
       if (!map) return;
-      const { fx } = map.toFraction(clientX, clientY);
+      const { fx, fy } = map.toFraction(clientX, clientY);
       const chars = ctx.chars;
       if (!chars.length) return;
-      // The boundary stays on its OWN line: candidates are the chars in
-      // the boundary rect's line band, and the finger's X picks the
-      // glyph (vertical finger movement is ignored — cross-line changes
-      // go through re-selection). A whole-table Euclidean scan here
-      // re-anchored onto the line ABOVE when the finger floated above
-      // the text (lifted handles).
-      const boundary =
-        which === "start" ? ctx.rects[0] : ctx.rects[ctx.rects.length - 1];
-      const bandTop = boundary[1] - 0.002;
-      const bandBottom = boundary[1] + boundary[3] + 0.002;
+      // Full 2D nearest glyph: the tip crosses lines freely (up/down)
+      // and moves along them (side to side). No line-band pin — the
+      // lifted handle's finger sits above the text, and a y-band filter
+      // here made vertical drags impossible (user report). Sliver rects
+      // stay impossible: the extent is a contiguous char span and the
+      // rects are its per-line unions.
       let best = 0;
       let bestD = Infinity;
       for (let i = 0; i < chars.length; i++) {
         const c = chars[i];
-        const cy = (c.y0 + c.y1) / 2;
-        if (cy < bandTop || cy > bandBottom) continue;
         const cx = (c.x0 + c.x1) / 2;
-        const d = (cx - fx) * (cx - fx);
+        const cy = (c.y0 + c.y1) / 2;
+        const d = (cx - fx) * (cx - fx) + (cy - fy) * (cy - fy);
         if (d < bestD) {
           bestD = d;
           best = i;