add reverse proxy config for PostHog

[maxnorm]

Summary

Changes Made

Checklist

Before submitting this PR, please ensure:

• Code follows the Solidity feature ban - No inheritance, constructors, modifiers, public/private variables, external library functions, using for directives, or selfdestruct

• Code follows Design Principles - Readable, uses diamond storage, favors composition over inheritance

• Code matches the codebase style - Consistent formatting, documentation, and patterns (e.g. ERC20Facet.sol)

• Code is formatted with forge fmt

• Existing tests pass - Run tests to be sure existing tests pass.

• New tests are optional - If you don't provide tests for new functionality or changes then please create a new issue so this can be assigned to someone.

• All tests pass - Run forge test and ensure everything works

• Documentation updated - If applicable, update relevant documentation

Make sure to follow the contributing guidelines.

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