perf: lazy-load xlsx/recharts, split estimate tabs, memoize nav

- xlsx dynamically imported via cached singleton in excel.ts and
  skillMatrixParser.ts (removes ~100 kB from 4 routes)
- recharts extracted into lazy-loaded SkillDistributionChart and
  PeakTimesChart components (removes ~60 kB from 3 routes)
- EstimateWorkspaceClient: 7 tab components + 2 editors loaded via
  next/dynamic (reduces /estimates/[id] from 323 kB to 138 kB)
- ImportModal lazy-loaded in ResourcesClient (deferred until open)
- NavItem memoized with React.memo, top 5 routes get prefetch=true
- Raw <img> replaced with next/image in ProjectsClient, CoverArtSection
- tRPC QueryClient: refetchOnWindowFocus/Reconnect disabled globally

Heaviest routes reduced 39-66% First Load JS:
  /analytics/skills: 383→132 kB (-66%)
  /estimates/[id]:   323→138 kB (-57%)
  /resources/[id]:   458→210 kB (-54%)
  /estimates:        310→170 kB (-45%)
  /resources:        363→222 kB (-39%)

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/src/app/(app)/projects/ProjectsClient.tsx

@@ -6,6 +6,7 @@ import { formatDate, formatMoney } from "~/lib/format.js";
 import type { Project, ColumnDef } from "@planarchy/shared";
 import { ProjectStatus, PROJECT_COLUMNS, BlueprintTarget } from "@planarchy/shared";
 import Link from "next/link";
+import Image from "next/image";
 import { clsx } from "clsx";
 import { motion } from "framer-motion";
 import { trpc } from "~/lib/trpc/client.js";
@@ -359,7 +360,7 @@ export function ProjectsClient() {
           <td key={col.key} className="max-w-xs truncate px-4 py-3 text-sm font-medium text-gray-900 dark:text-gray-100">
             <Link href={`/projects/${project.id}`} className="inline-flex items-center gap-2 transition hover:text-brand-600 hover:underline">
               {project.coverImageUrl ? (
-                <img src={project.coverImageUrl} alt="" className="h-6 w-6 flex-shrink-0 rounded object-cover" />
+                <Image src={project.coverImageUrl} alt={project.name} width={24} height={24} className="h-6 w-6 flex-shrink-0 rounded object-cover" unoptimized={project.coverImageUrl.startsWith("data:")} />
               ) : (
                 <span
                   className="flex h-6 w-6 flex-shrink-0 items-center justify-center rounded text-[9px] font-bold opacity-60"