This change removes the ViewerMode enum and instead infers whether to launch the Web Viewer or Native Viewer based on the graphics mode (gfx) setting. Specifically, setting gfx to "web" or "webgl" will now launch the Web Viewer (in future "webgpu" would also launch the Web Viewer).
Additionally, this unifies command-line flags across studio scripts and samples by replacing the --mjcf flag with --model (with positional argument fallback) and standardizing absl flags usage. --model is a better name since formats like .mjz and .mjb are also supported by this argument.
PiperOrigin-RevId: 959058940
Change-Id: If4e0ace664ddc6e45cb681d168679148e8c4901d
Following the export declarations in Dear ImGui and ImPlot METADATA, this change updates MuJoCo's Copybara configuration (copy.bara.sky) to export and transform the Python bindings. `//third_party/dear_imgui/google/py` exports to `python/mujoco/experimental/dear_imgui` and `//third_party/implot/google/py` exports to `python/mujoco/experimental/implot`.
PiperOrigin-RevId: 925293624
Change-Id: Ie6e32d247a6f7fc24bb36ae7060f2075d8efeb26
Matija Kecman