library: the page lit by its own records, and portraits that prove out

The expander reserves once on the page root instead of standing min-heights
on the grid; shelf heads carry artist portraits keyed by path; every record
tints its own card, expander and glow from its cover; the artwork opens the
shared viewer; the banner wash reads the playing record and actually paints
(isolation, the artist page's own fix); descriptions animate on both pages
via partAnim. Portrait resolution rejects placeholder rows and never stores
a silhouette (pick_artist_portrait, 3 tests); repair re-resolves the missing.

src/views/CatalogArtist.svelte

@@ -3816,6 +3816,39 @@
         };
     }
 
+    /** Fade+lift ONE element from its own mount, with the same WAAPI call
+     * `staggerIn` makes.
+     *
+     * The description needs this because `in:partIn` above never actually ran
+     * for it, and that was measured on this page: opening a Weezer record and
+     * sampling `.rail-lede` every frame gave opacity 1 on all 1389 frames cold
+     * and all 711 warm, with no transform at any point.
+     *
+     * Both of the other mechanisms miss it by construction. `staggerIn` is an
+     * action on .xp-panel and queries for its parts when that element is
+     * created, but the description block is created microseconds later — same
+     * flush — so the query finds nothing, which is why .rail-desc was left out
+     * of SWAP_PARTS in the first place. And Svelte plays an `in:` only for an
+     * element added by a later UPDATE; landing in the same flush is not one, so
+     * the intro is skipped too. An action always runs when its own element is
+     * created, whichever flush that is, so it covers every arrival time. */
+    function partAnim(node, { delay = 0 } = {}) {
+        if (reducedMotion()) return;
+        const rest = getComputedStyle(node).opacity || "1";
+        node.animate(
+            [
+                { opacity: 0, transform: "translateY(7px)" },
+                { opacity: rest, transform: "none" },
+            ],
+            {
+                duration: SWAP_MS * 0.7,
+                delay: delay * (SWAP_MS / 360),
+                easing: SWAP_EASE,
+                fill: "backwards",
+            },
+        );
+    }
+
     /** Hold the stage at an eased height that TRACKS the panel, rather than
      * animating once to a height measured up front. The panel is at its
      * smallest when the swap begins — no description, no track rows — so a
@@ -5269,19 +5302,19 @@
                                                      keeps its 4-line clamp and
                                                      its mask fade. -->
                                                 {#if railDesc.lede}
-                                                    <p class="rail-lede" in:partIn={{ delay: 55 }}>{railDesc.lede}</p>
+                                                    <p class="rail-lede" use:partAnim={{ delay: 55 }}>{railDesc.lede}</p>
                                                 {/if}
                                                 {#if railDesc.rest}
-                                                    <p class="rail-desc" class:clamped={!descExpanded} in:partIn={{ delay: 60 }}>{railDesc.rest}</p>
+                                                    <p class="rail-desc" class:clamped={!descExpanded} use:partAnim={{ delay: 60 }}>{railDesc.rest}</p>
                                                     <button
                                                         class="rail-more"
                                                         class:open={descExpanded}
-                                                        in:partIn={{ delay: 85 }}
+                                                        use:partAnim={{ delay: 85 }}
                                                         onclick={() => (descExpanded = !descExpanded)}
                                                     >{descExpanded ? "Show less" : "Show more"} <Icon name="chevron-down" size={13} /></button>
                                                 {/if}
                                                 {#if openInfo.genre || openInfo.label}
-                                                    <div class="rail-pills" in:partIn={{ delay: 100 }}>
+                                                    <div class="rail-pills" use:partAnim={{ delay: 100 }}>
                                                         {#if openInfo.genre}<span class="gpill accent">{openInfo.genre}</span>{/if}
                                                         {#if openInfo.label}<span class="gpill">{openInfo.label}</span>{/if}
                                                     </div>