style(frontend): Prettier config + one-time repo-wide format pass

Prettier 3 (pinned), printWidth 100, double quotes — chosen to match the existing
hand-formatting and minimise reflow. This commit is ONLY the mechanical format pass
(`prettier --write`) plus the config/ignore/scripts, isolated so it never pollutes a
feature diff. Verified behaviour-neutral: typecheck, eslint (0 errors), and vitest
all green before and after. See .git-blame-ignore-revs — `git blame` skips this sha.

frontend/src/lib/feedView.ts

@@ -34,17 +34,45 @@ export interface FeedViewSpec {
 
 // The whole matrix in one place. Adding a view here makes TS point at every switch that needs it.
 export const FEED_VIEW_SPEC: Record<FeedView, FeedViewSpec> = {
-  cards: { family: "card", minCol: 260, maxCol: null, thumb: true, dense: false, actionsBelow: false },
-  cardsSmall: { family: "card", minCol: 180, maxCol: null, thumb: true, dense: true, actionsBelow: false },
+  cards: {
+    family: "card",
+    minCol: 260,
+    maxCol: null,
+    thumb: true,
+    dense: false,
+    actionsBelow: false,
+  },
+  cardsSmall: {
+    family: "card",
+    minCol: 180,
+    maxCol: null,
+    thumb: true,
+    dense: true,
+    actionsBelow: false,
+  },
   // Single column on purpose: the point of the list is that your eye runs down one edge with the
   // titles stacked. Density must not cost that — `tiles` is the multi-column option instead.
   // Keeps the 896px cap: its actions dock at the right edge, so a wider row would only stretch the
   // dead space between them and the meta.
-  rows: { family: "row", minCol: null, maxCol: 896, thumb: true, dense: false, actionsBelow: false },
+  rows: {
+    family: "row",
+    minCol: null,
+    maxCol: 896,
+    thumb: true,
+    dense: false,
+    actionsBelow: false,
+  },
   // Much wider (1472): everything sits on one line and the columns after the title are fixed, so
   // there's no gap for the extra width to stretch — it all goes to the title. Raised from 1280 at
   // the user's request once they saw how much room was left over with the rail and filters hidden.
-  rowsCompact: { family: "row", minCol: null, maxCol: 1472, thumb: false, dense: false, actionsBelow: false },
+  rowsCompact: {
+    family: "row",
+    minCol: null,
+    maxCol: 1472,
+    thumb: false,
+    dense: false,
+    actionsBelow: false,
+  },
   // 380 = thumbnail (160) + gap (12) + ~192 for the text + the block's own padding (16). The text
   // floor is the action row's measured 156px plus enough for a title to be worth reading.
   // Tuned by measuring the real layouts, not guessed: 3 columns need 3n+32 px, so 380 turns the
@@ -52,7 +80,14 @@ export const FEED_VIEW_SPEC: Record<FeedView, FeedViewSpec> = {
   // (~955px) still gets 2. 470 was tried first and needed 956px for two — the common layout fell
   // back to ONE column and the mode looked broken; 400 then left 596px tiles whose titles ended
   // halfway, which is the very waste this mode exists to kill.
-  tiles: { family: "row", minCol: 380, maxCol: null, thumb: true, dense: false, actionsBelow: true },
+  tiles: {
+    family: "row",
+    minCol: 380,
+    maxCol: null,
+    thumb: true,
+    dense: false,
+    actionsBelow: true,
+  },
 };
 
 function isFeedView(v: unknown): v is FeedView {