refactor: batch operations and migrate to Odin 2026.05 APIs

[AmarBego]

Batch package operations to avoid repetitive per-package prompts:

• install: resolve all targets in a single resolution / transaction / prompt
• remove: pass all packages to one xbps-remove call for proper dep ordering
• update: group VUP upgrades by repo, skip per-package prompts after batch review
• transaction: group installs and removes by type+repo for single xbps calls
• xbps: add plural install/upgrade-from-repo variants accepting []string

Migrate to Odin 2026.05 APIs (no :os calls, updated signatures):

• make([]dynamic) -> [dynamic; N] inline array declarations
• os.read_entire_file / write_entire_file: use nil error checks
• os.make_directory + recursive logic -> os.make_directory_all
• fi.is_dir -> fi.type == .Directory, os.open returns (handle, err)
• remove unused core:io, core:os imports and parent_dir helper
• add vuru src install subcommand with host_install_pkg