Adds a two-step new thread modal: step one picks mode, step two
configures aspect ratio (Art mode only, six options) and resolution
(all modes: 1K/2K/4K). Settings are stored on the thread and forwarded
to the Gemini API on every send, retry, and edit. Also regenerates
icon.ico with Python to produce a clean all-BMP ICO compatible with
both Tauri's proc macro and llvm-rc cross-compilation.
## Summary
The Windows build job has been failing on every PR since the initial release. The root cause is that the default `clang`/`lld`/`llvm` apt packages resolve to an older version of `llvm-rc` that cannot handle PNG-compressed entries in `.ico` files — and all six images in `icon.ico` use PNG compression.
Pinning to `clang-18`, `lld-18`, and `llvm-18` (available in Ubuntu 24.04's default repos) and registering them via `update-alternatives` ensures `llvm-rc`, `clang-cl`, `lld-link`, and friends all resolve to a version that handles the icon resource correctly.
✨ This PR was created with help from Hikari~ 🌸
Reviewed-on: #17
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>
hikari
