Add Windows installer documentation

[dxy0218]

Summary

• document steps for building a Windows executable with PyInstaller and packaging it using Inno Setup
• add minimal requirements.txt

Testing

• python -m py_compile encrypted_chat/*.py

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https://chatgpt.com/codex/tasks/task_e_68bb0ee9c834832b856c4112f142c1ec

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

[P1] Include encryption key file in installer instructions

The packaging guide instructs Inno Setup to ship only encrypted_chat_client.exe, but the client code opens key.key on startup (encrypted_chat/encrypted_chat_client.py lines 4‑7). Following these steps produces an installer that installs an executable with no key file, so the application crashes with FileNotFoundError the first time the user launches it. Please update the instructions (and the Inno script example) to include or generate the key file alongside the executable so the installed client can actually start.

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