feat: subscription tiers, period filter, dashboards, docs

- Add subscription tiers (Basic/Pro/Business) with listing limits and dynamic commission
- Add daily/monthly period filter on rentals page
- Add landlord dashboard with earnings chart, stat cards, property performance
- Add landlord subscription management page
- Add tenant dashboard with upcoming stays
- Add business model documentation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/business-model.md

@@ -0,0 +1,56 @@
+# Revenue Model
+
+## Overview
+
+The platform generates revenue through 5 distinct streams, creating a diversified monetization strategy.
+
+## Revenue Streams
+
+### 1. Listing Fee (Marketplace)
+- **Amount:** $5 per marketplace listing
+- **Who pays:** Seller
+- **When:** At listing creation
+
+### 2. Marketplace Commission
+- **Rate:** 5% of sale price
+- **Who pays:** Seller (deducted from payout)
+- **When:** Upon successful sale completion
+
+### 3. Rental Commission
+- **Rate:** 5-10% of booking subtotal (varies by landlord subscription tier)
+- **Who pays:** Landlord (deducted from payout)
+- **When:** Upon booking completion
+
+| Tier | Commission Rate |
+|------|----------------|
+| BASIC | 10% |
+| PRO | 7% |
+| BUSINESS | 5% |
+
+### 4. Promoted Listings
+- **Rate:** $2.99 - $3.99 per day
+- **Who pays:** Seller / Landlord
+- **Description:** Boosted visibility in search results and category pages
+
+### 5. Subscription Plans
+
+| Plan | Monthly Price |
+|------|--------------|
+| BASIC | Free |
+| PRO | $9.99/month |
+| BUSINESS | $29.99/month |
+
+- **Who pays:** Landlord
+- **When:** Monthly recurring
+
+## Revenue Formula
+
+```
+Total Revenue = Listing Fees + Marketplace Commission + Rental Commission + Promotions + Subscriptions
+
+Monthly Revenue = (N_listings × $5)
+                + (GMV_marketplace × 0.05)
+                + (GMV_rental × avg_commission_rate)
+                + (N_promos × avg_promo_price × avg_days)
+                + (N_pro × $9.99 + N_business × $29.99)
+```