feat(omafiles): add keyboard-driven file explorer

[This-Is-NPC]

Adds omafiles, a keyboard-driven file explorer with a command line and a Qt
Quick window working over one index. Tags are the organizing layer, and nothing
is moved, renamed or wrapped to carry them.

Source: This-Is-NPC/omafiles · v0.1.0

Package

C++17 and Qt Quick built out of tree with qmake6 and make, in the same shape
as pkgbuilds/omawrite. .omarchy/package.json is {"source": "local"}. The
source is the GitHub tag tarball with a pinned sha256; nothing is fetched during
build().

Installs omafiles and omafiles-studio, the desktop entry, the hicolor SVG
icon and the MIT licence, with the same desktop-database and icon-cache
scriptlet omawrite uses.

Runtime dependencies are qt6-base and qt6-declarative for the window,
xdg-desktop-portal, xdg-utils for omafiles open, glib2 for
omafiles trash, and hicolor-icon-theme.

Verification

• Source archive SHA-256 047f2edc18c78b0566bbfcdcb2a58155245306814ce34f07ed424ef4d16d4a36 matches the tarball GitHub generates for v0.1.0.
• Every path package() installs is present in that tarball: omafiles.pro, LICENSE, pkgbuild/omafiles.svg, pkgbuild/omafiles.desktop.
• cli.pro and studio.pro point DESTDIR at ../../bin, which lands as build/bin for the out-of-tree build build() does — the paths package() reads.
• Upstream suite at the tag: 65 passed, 0 failed, 1 skipped (the documentation-shot writer, which needs OMAFILES_DOCS=1).

Not covered: no makepkg or bin/repo build run yet, and only x86_64 has been
built and used — aarch64 is declared but untested.