fix(reader): arrows stay page turns while the progress slider holds focus

Clicking the bottom progress slider left it focused, and the reader's
keydown guard treats INPUT focus as typing — so arrow keys stepped the
range input instead of turning pages. With step="any" each press moved
~1% of the book and key repeat crossed the whole book in seconds; the
debounced progress saves then persisted every wild landing (positions
scattered from page 5 to 285 to 100%, "progress no longer saves
correctly after page turns").

Two layers:
- reader.templ: all three progress sliders blur on pointerup, so a
  mouse scrub no longer leaves focus behind.
- reader.ts handleKeydown: ArrowLeft/ArrowRight on a focused progress
  slider preventDefault, blur, and fall through to the page-turn
  handlers; every other key still belongs to the control, so a
  keyboard user who Tabbed to the slider keeps arrows for it.

web/src/reader/reader.ts

@@ -3993,6 +3993,8 @@ document.addEventListener("alpine:init", () => {
       // Escape stays live so popovers/drawers can still be dismissed from
       // the keyboard even mid-note.
       const t = event.target as HTMLElement | null;
+      const isProgressSlider =
+        t instanceof HTMLInputElement && t.type === "range" && t.id.startsWith("progress-slider");
       const typing =
         t?.tagName === "INPUT" ||
         t?.tagName === "SELECT" ||
@@ -4000,7 +4002,17 @@ document.addEventListener("alpine:init", () => {
         !!t?.isContentEditable;
       // NOTE: no chrome poke here — keyboard page turns are reading
       // actions and must leave the chrome alone (handoff item 7).
-      if (typing && k !== "Escape") return;
+      if (typing && k !== "Escape") {
+        // A focused progress range swallows arrows as ~1% book-jumps —
+        // with key repeat, holding an arrow crosses the entire book in
+        // seconds and the debounced saves persist every wild landing
+        // (2026-10-21 incident). Arrows are page turns everywhere in the
+        // reader: release the slider and fall through to the turn
+        // handlers. Every other key still belongs to the control.
+        if (!(isProgressSlider && (k === "ArrowLeft" || k === "ArrowRight"))) return;
+        event.preventDefault();
+        t.blur();
+      }
       if (k === "ArrowLeft" || k === "h") {
         if (event.altKey) {
           event.preventDefault();