chore(lint): manual cleanup batch 3/3 — finish noArrayIndexKey + format pass

- group 6 finished: convert remaining 9 Array.from skeleton patterns (index, demo, search, history) using KEYS_N + dynamicKeys helpers
- biome-ignore for legitimate column-index keys in column-stack components
- biome --write format pass

Lint count: 218 → 155 (614/769 fixed cumulatively, 80%).

Remaining (legacy): 121 noExplicitAny + 42 noNonNullAssertion + ~9 small. These need typed refactors and aren't safe to auto-fix (--unsafe drops the ! assertions and breaks strict TS); deferred to a follow-up.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/components/catalog/model-list-columns.tsx

@@ -291,6 +291,7 @@ export function ModelListColumns({
       >
         {columns.map((col, colIdx) => (
           <div
+            // biome-ignore lint/suspicious/noArrayIndexKey: columns are append/pop only — index is the stable identity here
             key={colIdx}
             className={cn(
               "w-[220px] shrink-0 overflow-y-auto",