fix: Health check API + Portfolio UX improvements

API FIX:
- quickHealthCheck now uses POST method (was GET)
- Fixes 'int_parsing' error for domain_id

PORTFOLIO UX:
1. Health Check now works correctly with POST /domains/health-check

2. Clear separation of List vs Sell:
   - 'List' button → Opens listing form (marketplace)
   - 'Sold?' button → Records completed sale (P&L tracking)

3. Improved Valuation Modal:
   - Shows 'Pounce Score Estimate' instead of just 'Estimated Value'
   - Color-coded confidence badge (high/medium/low)
   - Clear disclaimer about algorithmic estimate

4. Record Sale Modal:
   - Clear explanation of purpose (P&L tracking)
   - Hint to use 'List' button for marketplace

LISTINGS PAGE:
- Accepts ?domain= query parameter
- Auto-opens create modal with prefilled domain
- Seamless flow from Portfolio → List on Marketplace

frontend/src/app/command/listings/page.tsx

@@ -1,6 +1,7 @@
 'use client'
 
 import { useEffect, useState } from 'react'
+import { useSearchParams } from 'next/navigation'
 import { useStore } from '@/lib/store'
 import { api } from '@/lib/api'
 import { CommandCenterLayout } from '@/components/CommandCenterLayout'
@@ -61,11 +62,13 @@ interface VerificationInfo {
 
 export default function MyListingsPage() {
   const { subscription } = useStore()
+  const searchParams = useSearchParams()
+  const prefillDomain = searchParams.get('domain')
   
   const [listings, setListings] = useState<Listing[]>([])
   const [loading, setLoading] = useState(true)
   
-  // Modals
+  // Modals - auto-open if domain is prefilled
   const [showCreateModal, setShowCreateModal] = useState(false)
   const [showVerifyModal, setShowVerifyModal] = useState(false)
   const [selectedListing, setSelectedListing] = useState<Listing | null>(null)
@@ -89,6 +92,14 @@ export default function MyListingsPage() {
     loadListings()
   }, [])
 
+  // Auto-open create modal if domain is prefilled from portfolio
+  useEffect(() => {
+    if (prefillDomain) {
+      setNewListing(prev => ({ ...prev, domain: prefillDomain }))
+      setShowCreateModal(true)
+    }
+  }, [prefillDomain])
+
   const loadListings = async () => {
     setLoading(true)
     try {

frontend/src/app/command/portfolio/page.tsx

@@ -25,6 +25,7 @@ import {
   Activity,
   Shield,
   AlertTriangle,
+  Tag,
 } from 'lucide-react'
 
 // Health status configuration
@@ -447,11 +448,20 @@ export default function PortfolioPage() {
                     onClick={() => openEditModal(domain)}
                     title="Edit"
                   />
+                  <Link
+                    href={`/command/listings?domain=${encodeURIComponent(domain.domain)}`}
+                    onClick={(e) => e.stopPropagation()}
+                    className="px-3 py-2 text-xs font-medium text-accent hover:bg-accent/10 rounded-lg transition-colors flex items-center gap-1"
+                  >
+                    <Tag className="w-3 h-3" />
+                    List
+                  </Link>
                   <button
                     onClick={(e) => { e.stopPropagation(); openSellModal(domain) }}
-                    className="px-3 py-2 text-xs font-medium text-accent hover:bg-accent/10 rounded-lg transition-colors"
+                    className="px-3 py-2 text-xs font-medium text-foreground-muted hover:bg-foreground/5 rounded-lg transition-colors"
+                    title="Record a completed sale (for P&L tracking)"
                   >
-                    Sell
+                    Sold?
                   </button>
                   <TableActionButton
                     icon={Trash2}
@@ -586,10 +596,14 @@ export default function PortfolioPage() {
         </Modal>
       )}
 
-      {/* Sell Modal */}
+      {/* Record Sale Modal - for tracking completed sales */}
       {showSellModal && selectedDomain && (
-        <Modal title={`Sell ${selectedDomain.domain}`} onClose={() => setShowSellModal(false)}>
+        <Modal title={`Record Sale: ${selectedDomain.domain}`} onClose={() => setShowSellModal(false)}>
           <form onSubmit={handleSellDomain} className="space-y-4">
+            <div className="p-3 bg-accent/10 border border-accent/20 rounded-lg text-sm text-foreground-muted">
+              <p>Record a completed sale to track your profit/loss. This will mark the domain as sold in your portfolio.</p>
+              <p className="mt-2 text-accent">Want to list it for sale instead? Use the <strong>"List"</strong> button.</p>
+            </div>
             <div className="grid grid-cols-2 gap-4">
               <div>
                 <label className="block text-sm text-foreground-muted mb-1.5">Sale Price *</label>
@@ -647,16 +661,26 @@ export default function PortfolioPage() {
             <div className="space-y-4">
               <div className="text-center p-6 bg-accent/5 border border-accent/20 rounded-xl">
                 <p className="text-4xl font-display text-accent">${valuation.estimated_value.toLocaleString()}</p>
-                <p className="text-sm text-foreground-muted mt-1">Estimated Value</p>
+                <p className="text-sm text-foreground-muted mt-1">Pounce Score Estimate</p>
               </div>
               <div className="space-y-2 text-sm">
-                <div className="flex justify-between p-3 bg-foreground/5 rounded-lg">
-                  <span className="text-foreground-muted">Confidence</span>
-                  <span className="text-foreground capitalize font-medium">{valuation.confidence}</span>
+                <div className="flex justify-between items-center p-3 bg-foreground/5 rounded-lg">
+                  <span className="text-foreground-muted">Confidence Level</span>
+                  <span className={clsx(
+                    "px-2 py-0.5 rounded text-xs font-medium capitalize",
+                    valuation.confidence === 'high' && "bg-accent/20 text-accent",
+                    valuation.confidence === 'medium' && "bg-amber-400/20 text-amber-400",
+                    valuation.confidence === 'low' && "bg-foreground/10 text-foreground-muted"
+                  )}>
+                    {valuation.confidence}
+                  </span>
                 </div>
-                <div className="flex justify-between p-3 bg-foreground/5 rounded-lg">
-                  <span className="text-foreground-muted">Formula</span>
-                  <span className="text-foreground font-mono text-xs">{valuation.valuation_formula}</span>
+                <div className="p-3 bg-foreground/5 rounded-lg">
+                  <p className="text-foreground-muted mb-1">Valuation Formula</p>
+                  <p className="text-foreground font-mono text-xs break-all">{valuation.valuation_formula}</p>
+                </div>
+                <div className="p-3 bg-amber-400/10 border border-amber-400/20 rounded-lg text-xs text-amber-400">
+                  <p>This is an algorithmic estimate based on domain length, TLD, and market patterns. Actual market value may vary.</p>
                 </div>
               </div>
             </div>

frontend/src/lib/api.ts

@@ -385,7 +385,9 @@ class ApiClient {
 
   // Quick health check for any domain (premium)
   async quickHealthCheck(domain: string) {
-    return this.request<DomainHealthReport>(`/domains/health-check?domain=${encodeURIComponent(domain)}`)
+    return this.request<DomainHealthReport>(`/domains/health-check?domain=${encodeURIComponent(domain)}`, {
+      method: 'POST',
+    })
   }
 
   // TLD Pricing