feat: Sprint 3 — automation, intelligence, skill marketplace

Auto-Staffing Suggestions (A6):
- generateAutoSuggestions() ranks top-3 resources on demand creation
- Uses existing staffing engine (skill 40%, availability 30%, cost 20%, util 10%)
- Creates in-app notification with match scores for managers
- Triggered after createDemandRequirement and partial fillDemandRequirement

Vacation Conflict Detection (A7):
- checkVacationConflicts() warns when >50% chapter absent on same days
- Returns warnings array in approve/batchApprove responses (advisory, non-blocking)
- Creates VACATION_CONFLICT_WARNING notification for approver

Weekly Chargeability Alerts (A10):
- checkChargeabilityAlerts() finds resources >15pp below target
- Cron endpoint: GET /api/cron/chargeability-alerts
- Duplicate-safe by resourceId + month composite key

Rate Card Auto-Apply (A11):
- lookupRate() finds best matching rate card line (weighted scoring)
- Auto-fills demand line rates in estimate create/updateDraft when rates are 0
- Marks auto-filled lines with metadata.autoAppliedRateCard
- New lookupDemandLineRate query for on-demand UI lookups

Public Holiday Auto-Import (A12):
- autoImportPublicHolidays() generates holidays by resource federal state
- Cron endpoint: GET /api/cron/public-holidays?year=2027
- Duplicate-safe, uses existing getPublicHolidays() from shared

Skill Marketplace MVP (G6):
- New page: /analytics/skill-marketplace with 3 sections
- Skill Search: filter by name, proficiency, availability, sortable results
- Skill Gap Heat Map: supply vs demand per skill, shortage/surplus indicators
- Skill Distribution: top-20 horizontal bar chart (reuses SkillDistributionChart)
- New getSkillMarketplace query in resource router
- Sidebar nav link under Analytics for ADMIN/MANAGER/CONTROLLER

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

apps/web/src/components/layout/AppShell.tsx

@@ -55,6 +55,9 @@ function RolesIcon() {
 function SkillsIcon() {
   return <svg className="h-4 w-4" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.8} d="M12 3l2.8 5.7 6.2.9-4.5 4.4 1 6.2L12 17.2 6.5 20.2l1-6.2L3 9.6l6.2-.9L12 3z" /></svg>;
 }
+function MarketplaceIcon() {
+  return <svg className="h-4 w-4" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.8} d="M3 3h18l-2 9H5L3 3zm0 0l-1-1m6 16a1 1 0 102 0 1 1 0 00-2 0zm10 0a1 1 0 102 0 1 1 0 00-2 0zM5 12h14" /></svg>;
+}
 function ChargeabilityIcon() {
   return <svg className="h-4 w-4" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.8} d="M5 17l4-4 3 3 7-8M19 19H5V5" /></svg>;
 }
@@ -136,6 +139,7 @@ const navSections: NavSection[] = [
     label: "Analytics",
     items: [
       { href: "/analytics/skills", label: "Skills Analytics", icon: <SkillsIcon />, roles: ["ADMIN", "MANAGER", "CONTROLLER", "VIEWER"] },
+      { href: "/analytics/skill-marketplace", label: "Skill Marketplace", icon: <MarketplaceIcon />, roles: ["ADMIN", "MANAGER", "CONTROLLER"] },
       { href: "/reports/chargeability", label: "Chargeability", icon: <ChargeabilityIcon />, roles: ["ADMIN", "MANAGER", "CONTROLLER"] },
       { href: "/analytics/computation-graph", label: "Computation Graph", icon: <GraphIcon />, roles: ["ADMIN", "MANAGER", "CONTROLLER"] },
     ],