docs: explain example sources and fix fullscreen restore failure

[antono3]

Add purpose comments to all 30 maintained source/script/header files, extend the source map, and replace obsolete README script names with the V-native commands present at IMGUI_REVISION.

Also preserve normal restore bounds when toggling a maximized window through fullscreen. The Linux compile and portable-package jobs failed the existing shortcut test because the explicit glfw.restore_window call before entering fullscreen races the window manager's state transitions. Enter fullscreen directly while retaining the prior maximized flag; the existing exit path restores maximization. The geometry assertions are unchanged.

Validation:

• The original CI-built docking binaries reproduced the normal-restore failure locally under Xvfb/Openbox.
• Eight consecutive unchanged shortcut-suite runs passed against those binaries with a temporary LD_PRELOAD shim suppressing glfwRestoreWindow, isolating the removed call. This diagnostic is not shipped.
• The modified shortcut source compiles and passes eight cycles in a small GLFW host. That host uses slower key injection to avoid missing polled keys; it is supporting evidence, not a substitute for application CI.
• Documentation shell syntax, tool/launcher compilation and launcher --help passed earlier; git diff --check passes. Documentation-only changes leave executable lines unchanged except for the deliberate fullscreen fix.

Full application rebuilds, Windows behavior, Android/device tests and packaging await CI. setup.vsh still calls the removed run_demo_windows.ps1 on Windows; the README documents the available upstream run_demo.vsh route. That separate launcher defect remains maintenance follow-up.