Make table page size a configurable setting, not a hardcoded 20

Pagination just landed hardcoded to 20 rows everywhere; add a way to
change that instead of leaving it fixed for every table in the app.

pageSize joins dateFormat/timeFormat on the existing display settings
object (server-side default 20, 5-500 range enforced by the PUT
schema) rather than becoming its own settings section, since it's the
same kind of thing -- an admin-configured, globally-applied display
preference read by every signed-in role via the already-public GET
/api/settings/display endpoint, same as the date/time format already
works.

Renamed the "Date & Time" settings tab/page/route to "Display" (still
just one component, now covering both date/time format and table
pagination) since its scope no longer matches the old name -- kept
Settings.tsx's usual pattern of one page per concern rather than
adding a second, oddly-scoped tab just for one number field.

New web/src/utils/pageSize.ts mirrors utils/date.ts's existing
module-level "set once at startup, read anywhere without prop-
drilling" pattern; usePagination()'s pageSize parameter now defaults
to getPageSize() instead of a literal 20, evaluated fresh on every
call so it picks up a saved change without touching any of the ten
pages already using the hook.

Verified server-side against a temp SQLite DB: pageSize defaults to
20, a partial update sets it without disturbing dateFormat/timeFormat
and vice versa, and it persists across a fresh settings read. Also
checked the default-parameter mechanics directly (re-evaluates the
global value on every call rather than capturing it once, and an
explicit override still wins).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

server/src/routes/settings.ts

@@ -66,7 +66,10 @@ const updateSchema = z.object({
     .optional(),
   providerColors: z.record(z.string()).optional(),
   integrationColors: z.record(z.string()).optional(),
-  display: z.object({ dateFormat: z.enum(["ymd", "dmy", "mdy"]), timeFormat: z.enum(["24h", "12h"]) }).partial().optional(),
+  display: z
+    .object({ dateFormat: z.enum(["ymd", "dmy", "mdy"]), timeFormat: z.enum(["24h", "12h"]), pageSize: z.number().int().min(5).max(500) })
+    .partial()
+    .optional(),
 });
 
 settingsRouter.put("/", requireRole("admin"), asyncHandler(async (req, res) => {