refactor(ci): skip bincraft reinstall when image already has it

bincraft is baked into the build-env images, but every workflow run
unconditionally called pak::pak("git::.../bincraft.git") to defend
against bakes where the install silently failed.
That cost ~30-60s per job (pak resolves Remotes, may recompile),
which adds up across all process-updates, update-package-index,
weekly-rebuild and archive-missed-packages workflows.

Guard the call with requireNamespace(): healthy images skip the
install entirely; broken images still self-heal.

.crow/archive-missed-packages.yaml

@@ -55,7 +55,7 @@ steps:
       GIT_USER: pat-s
       R_VERSION: 4.5.3
     commands:
-      - /opt/R/$R_VERSION/bin/R -q -e 'pak::pak("git::https://codefloe.com/rpkgs/bincraft.git", dependencies = TRUE)'
+      - /opt/R/$R_VERSION/bin/R -q -e 'if (!requireNamespace("bincraft", quietly = TRUE)) pak::pak("git::https://codefloe.com/rpkgs/bincraft.git", dependencies = TRUE)'
       - /opt/R/$R_VERSION/bin/R -q -e 'packageVersion("bincraft")'
       - /opt/R/$R_VERSION/bin/R -q -e 'bincraft::process_unarchived_pkgs(Sys.getenv("CODENAME"), Sys.getenv("ARCH"), workers = 2L)'
     backend_options: