Handle chunked encoding

[halkeye]

fixes #71 / #70

Use StreamUtils library to handle http chucked encoding responses.

[halkeye]

moved it earlier to do less memory management. getString() handles chunked, and errors probably shoudn't hopefully maybe be binary

[halkeye]

works for me on my inkplate6v2

[lanrat]

Thanks for working on this! The chunked encoding issue is real and needs fixing.

However, I think we can solve this without adding an external library. The ESP32 HTTPClient already has full chunked transfer encoding support built in — the issue is that httpGet() reads from http.getStreamPtr() (raw WiFiClient*), which bypasses the library's decoding. The built-in writeToStream() method handles both chunked and identity encoding transparently — it's the same code path getString() uses internally.

The fix would be to write a small BufferStream shim (~25 lines) that wraps the existing ps_malloc buffer with the Stream interface, then replace the manual read loop with http.writeToStream(&bs). This avoids adding a new dependency, saves flash on an already-constrained ESP32, and requires less code overall.

Note: I did use a LLM to help me research writeToStream(). If the above is incorrect, you may push back. I have a strong preference for not adding additional libraries when not needed for embedded projects.