docs(sprint2): update with Entropia Nexus API discovery

- Official REST API found at api.entropianexus.com
- Update integration strategy to use API instead of scraping
- Sprint 2 plan now reflects real API approach

docs/Sprint2-Plan.md

@@ -0,0 +1,98 @@
+# Sprint 2: GUI Foundation + Loadout Manager
+
+**Date:** 2026-02-08  
+**Status:** IN PROGRESS  
+**Lead Engineer:** LemonNexus  
+**Objective:** Build PyQt6 GUI with transparent HUD overlay + Entropia Nexus loadout manager
+
+---
+
+## Sprint 2 Scope
+
+### Phase 1: GUI Foundation (PyQt6)
+- [ ] Main application window
+- [ ] Transparent HUD overlay (always-on-top, click-through)
+- [ ] Real-time stats display panel
+- [ ] Session controls (start/stop/pause)
+- [ ] Theme system (dark/light)
+
+### Phase 2: Loadout Manager
+- [ ] Weapon/Armor/Tool configuration UI
+- [ ] Entropia Nexus API client (stats fetching)
+- [ ] Cost calculations (PED/hour, PED/drop)
+- [ ] Loadout save/load system
+- [ ] DPP (Damage Per Pec) calculator
+
+### Phase 3: Integration
+- [ ] Connect HUD to live session data
+- [ ] Display current loadout stats
+- [ ] Real-time cost tracking
+- [ ] ROI calculations with gear costs
+
+---
+
+## Technical Stack
+
+| Component | Technology |
+|-----------|------------|
+| GUI Framework | PyQt6 6.4+ |
+| Overlay | Qt Widgets with WA_TransparentForMouseEvents |
+| Styling | QSS (Qt StyleSheets) |
+| API Client | httpx (async) |
+| Data Storage | SQLite (existing) |
+
+---
+
+## Development Notes
+
+**Self-Testing Strategy:**
+- Use mock data for UI development
+- Test overlay positioning with fake stats
+- Validate Entropia Nexus API integration
+- Simulate loadout changes
+
+**User Testing Required For:**
+- Real Entropia Nexus API responses
+- Actual gear stats validation
+- In-game HUD positioning
+- Live loadout switching
+
+---
+
+## Architecture
+
+```
+/ui
+  /components      → Reusable widgets
+  /windows         → Main window, HUD overlay
+  /themes          → QSS stylesheets
+  /loadout         → Loadout manager UI
+/core
+  /nexus_api.py    → Entropia Nexus client (expand)
+  /loadout.py      → Loadout data models
+```
+
+---
+
+## Entropia Nexus Integration
+
+**Status:** ✅ OFFICIAL REST API FOUND!
+
+**API Docs:** https://api.entropianexus.com/docs/
+
+**Approach:** Use official REST API (no scraping needed!)
+
+**Endpoints to Explore:**
+- `/items` — Weapon/Armor/Tool stats
+- `/weapons` — Weapon-specific data
+- `/markets` — Markup data (optional)
+
+**Data Needed:**
+- Weapon: damage, decay, ammo, DPP
+- Armor: protection values, decay
+- Tools: depth, radius, cost
+- Market: markups (optional)
+
+---
+
+**Next Update:** When Phase 1 (GUI Foundation) is ready for review