feat: sticky locked-image thumbnail while scrolling; two-click preview-then-open on the portfolio index

the locked image now gets a small pinned copy (18rem, same width as the text column) that appears once the real preview scrolls out of view and disappears again once the text runs out — fixed-position + scroll-driven rather than CSS sticky, since the filebrowser box is only ever as tall as its own content, not the much taller text next to it.\n\nalso scoped the existing click-outside-unfreezes-the-lock listener to clicks inside .filebrowser only, since with listings now starting locked, a click to read or select a word in the text would otherwise silently kill the sticky preview.\n\nportfolio index: rows there are real links (href + data-img together), so a single click used to jump straight into the project — the only way to preview a different one first was hovering, which does nothing for touch and is now also blocked while something is locked. first click on a different project now just previews it (like hover used to); a second click on the same row, or clicking the preview image itself, opens it.

assets/js/filebrowser.js

@@ -4,12 +4,54 @@
 (function () {
   "use strict";
   var rows = [], img = null, texts = [], cap = null, cur = 0, frozen = false, container = null, player = null, pv = null;
+  var layout = null, mainPreview = null, sticky = null, stickyImg = null;
 
   function hideTexts() { texts.forEach(function (t) { t.hidden = true; }); }
   function showText(k) { texts.forEach(function (t) { t.hidden = (t.getAttribute("data-text") !== k); }); }
   function hidePlayer() { if (player) { player.hidden = true; if (pv && !pv.paused) pv.pause(); } }
   function showPlayer() { if (player) player.hidden = false; }
-  function setFrozen(v) { frozen = v; if (container) container.classList.toggle("is-frozen", v); }
+  function setFrozen(v) { frozen = v; if (container) container.classList.toggle("is-frozen", v); syncSticky(); }
+
+  // small pinned copy of the locked image, shown to the left of the text
+  // column once the real preview has scrolled out of view — mirrors the
+  // LOCKED row only (like the main preview already does once frozen), never
+  // the hover state, and only for as long as there's still text alongside it.
+  function ensureSticky() {
+    if (sticky) return;
+    sticky = document.createElement("div");
+    sticky.className = "proj-sticky";
+    stickyImg = document.createElement("img");
+    stickyImg.alt = "";
+    sticky.appendChild(stickyImg);
+    document.body.appendChild(sticky);
+  }
+  function syncSticky() {
+    if (!sticky) return;
+    var a = frozen ? rows[cur] : null;
+    var src = a ? a.getAttribute("data-img") : null;
+    if (src && layout && mainPreview) {
+      if (stickyImg.getAttribute("src") !== src) stickyImg.src = src;
+      updateStickyVisibility();
+    } else {
+      sticky.classList.remove("is-visible");
+    }
+  }
+  function updateStickyVisibility() {
+    if (!sticky || !stickyImg.getAttribute("src") || !layout || !mainPreview) return;
+    if (!window.matchMedia("(min-width: 1100px)").matches) { sticky.classList.remove("is-visible"); return; }
+    var pr = mainPreview.getBoundingClientRect();
+    var lr = layout.getBoundingClientRect();
+    var show = pr.bottom < 0 && lr.bottom > 0;
+    sticky.classList.toggle("is-visible", show);
+  }
+  var stickyTick = false;
+  function onScrollOrResize() {
+    if (stickyTick) return;
+    stickyTick = true;
+    requestAnimationFrame(function () { stickyTick = false; updateStickyVisibility(); });
+  }
+  window.addEventListener("scroll", onScrollOrResize, { passive: true });
+  window.addEventListener("resize", onScrollOrResize);
 
   // tell the shell to "type" the matching command. navigable rows (those with an
   // href: ".." and the portfolio project folders) are directories → `cd`; the
@@ -71,18 +113,47 @@
     pv = player ? player.querySelector("video") : null;
     cap = document.querySelector(".tui__status");
     cur = 0; frozen = false;
-    if (!rows.length) return;
+
+    layout = document.querySelector(".proj-layout");
+    mainPreview = document.querySelector(".filebrowser .tui__preview");
+    ensureSticky();
+    sticky.classList.remove("is-visible");
+    if (!rows.length) { layout = null; return; }
 
     rows.forEach(function (a, i) {
+      // portfolio-index rows are real links (data-img + href together) — a
+      // single click there used to jump straight into the project, which
+      // meant hovering was the only way to preview a different one first.
+      // now the first click just previews it (same as the old hover did);
+      // only a second click on the already-previewed row, or the preview
+      // image itself, actually navigates.
+      var isProjectLink = a.hasAttribute("href") && a.hasAttribute("data-img");
       a.addEventListener("mouseenter", function () { if (!frozen) select(i); });
       a.addEventListener("click", function (e) {
-        if (a.getAttribute("href")) return;        // navigation rows behave normally
+        if (isProjectLink) {
+          if (frozen && cur === i) return;   // already previewed — let the link through
+          e.preventDefault();
+          select(i);
+          setFrozen(true);
+          return;
+        }
+        if (a.getAttribute("href")) return;        // ".." navigates normally
         e.preventDefault();
         if (frozen && cur === i) { setFrozen(false); ghostClear(); }
         else { select(i); setFrozen(true); }
       });
     });
 
+    if (img) {
+      img.onclick = function () {
+        var a = rows[cur];
+        if (a && a.hasAttribute("href") && a.hasAttribute("data-img")) {
+          var href = a.getAttribute("href");
+          if (window.pjax) window.pjax(href); else window.location.href = href;
+        }
+      };
+    }
+
     var start = rows.findIndex(function (a) { return a.classList.contains("is-selected"); });
     select(start < 0 ? 0 : start, true);   // initial selection: don't echo into the shell yet
     // portfolio/about listings start pre-locked on their first file, same as a
@@ -98,8 +169,13 @@
   }
 
   // one-time document listeners (reference the current bound state)
+  // clicking elsewhere IN THE WIDGET (the preview image, blank space in the
+  // list) releases the lock; clicks out in the text/page don't — now that
+  // listings start locked, a click to read or select a word shouldn't kill
+  // the sticky preview underneath it.
   document.addEventListener("click", function (e) {
     if (e.target.closest && e.target.closest(".tui__ls a")) return;
+    if (!(e.target.closest && e.target.closest(".filebrowser"))) return;
     if (frozen) { setFrozen(false); ghostClear(); }
   });
   document.addEventListener("keydown", function (e) {