Add OrbitHub C++ Qt Widgets spec and Codex prompts

docs/OrbitHub_v0_Spec_CPP_QtWidgets.md

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+# OrbitHub v0 Specification (Pure C++ / Qt6 Widgets)
+
+## Overview
+
+OrbitHub is a cross-platform native desktop application for managing and launching remote sessions.
+
+Platforms:
+- Windows 11
+- Linux (Mint/Ubuntu-family)
+- macOS
+
+Implementation:
+- 100% C++
+- Qt 6 Widgets (no Qt Quick)
+- CMake build system
+- MIT License
+
+This replaces the earlier Python-based architecture.
+
+---
+
+## UX Model
+
+OrbitHub uses a two-window model:
+
+1) Profiles Window (single instance)
+- List of saved profiles
+- Search box
+- New / Edit / Delete
+- Double-click connects
+
+2) Session Window(s)
+- QTabWidget
+- One tab per session
+- Close tab destroys session
+- Placeholder view widget displays:
+  "OrbitHub Native Surface"
+
+---
+
+## Milestone 0
+
+- Fresh C++/Qt repo scaffold
+- App builds
+- Profiles window launches
+- Session window opens with placeholder tab
+- Tag: v0-m0-done
+
+---
+
+## Milestone 1
+
+- SQLite integration
+- Profiles CRUD
+- Connect loads profile name into tab
+- Tag: v0-m1-done