feat: create autonomous Nivora package repository

Maintain a validated cross-distribution package catalog.
Automate upstream updates, isolated builds, diagnostics, and direct publication.
Build the official GitHub Desktop sources for Linux with working OAuth.

yandex-browser-stable/postinstall.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+
+set -euo pipefail
+
+optional_refresh() {
+    local label=$1
+    shift
+    if ! "$@"; then
+        echo "Предупреждение: не удалось обновить ${label}." >&2
+    fi
+}
+
+sandbox=/opt/yandex/browser/yandex_browser-sandbox
+if [[ ! -f "$sandbox" ]]; then
+    echo "Ошибка: не найден Chromium sandbox: ${sandbox}" >&2
+    exit 1
+fi
+if [[ -L /proc/self/ns/user ]] && command -v unshare >/dev/null 2>&1 \
+    && unshare --user true 2>/dev/null; then
+    chmod 0755 "$sandbox"
+else
+    chmod 4755 "$sandbox"
+fi
+
+codec_dir=/opt/yandex/browser
+if [[ -x "${codec_dir}/update_codecs" ]]; then
+    rm -f -- "${codec_dir}/libffmpeg.so" "${codec_dir}/codecs_checksum"
+    if ! "${codec_dir}/update_codecs" "$codec_dir"; then
+        echo "Предупреждение: не удалось установить дополнительные медиакодеки." >&2
+    fi
+fi
+
+if command -v update-desktop-database >/dev/null 2>&1; then
+    optional_refresh "desktop-базу" update-desktop-database -q /usr/share/applications
+fi
+if command -v update-mime-database >/dev/null 2>&1; then
+    optional_refresh "базу MIME" update-mime-database /usr/share/mime
+fi
+if command -v gtk-update-icon-cache >/dev/null 2>&1; then
+    optional_refresh "кэш иконок" gtk-update-icon-cache -f -q /usr/share/icons/hicolor
+fi
+if command -v kbuildsycoca6 >/dev/null 2>&1; then
+    optional_refresh "кэш KDE" kbuildsycoca6 --noincremental
+elif command -v kbuildsycoca5 >/dev/null 2>&1; then
+    optional_refresh "кэш KDE" kbuildsycoca5 --noincremental
+fi