chore: resolve latest bincraft release dynamically (no hardcoded pins) (#107)

## Summary

Stop hardcoding the bincraft version. Every `.crow` workflow and the build-one image pinned `@vX.Y.Z` (and a `packageVersion() != "X.Y.Z"` guard), so each bincraft release meant editing the version in ~8 places — and it was easy to miss one (the Dockerfile lagged at v4.2.1; v4.4.1 shipped without the empty-env fix because of exactly this churn).

## Change

New `local/install-bincraft.R` resolves the **latest release tag dynamically**:

- `git ls-remote --tags` on the public repo (no token),
- keep `vX.Y.Z` tags, pick the highest version (filtered/sorted in R for portability, not via git `--sort`/refspec which behaved inconsistently under `system2()`),
- `pak::pak("git::…@<latest>")` — idempotent on the git ref, so re-runs keep the package unless a newer tag exists.

All call sites now invoke the helper instead of a pinned version:

- `.crow/build-all-versions.yaml` (primary + per-minor pass)
- `.crow/build-all-versions-install-deps.yaml`
- `.crow/process-updates.yaml` (primary + per-minor pass)
- `.crow/weekly-rebuild-missing.yaml`
- `.crow/archive-missed-packages.yaml`
- `docker/build-one.Dockerfile` (ships the helper into the image; `ensure_bincraft` sources it)

## Effect

Tag a new bincraft release → the next CI run / `just rebuild` picks it up automatically. No more pin edits, and no more "forgot to bump the Dockerfile" drift.

## Verified

- Resolver returns the current latest tag (`v4.4.2`) via `git ls-remote` + R-side version sort.
- All five workflow YAMLs parse; helper R parses; air/editorconfig clean.

Note: this tracks the latest **tag**, so cutting a release is still the deliberate gate — CI won't pick up un-tagged main.
Reviewed-on: #107

.crow/process-updates.yaml

@@ -195,7 +195,7 @@ steps:
     commands:
       - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
       - rm -rf /mnt/cache/R-pkgs/00LOCK-* /mnt/cache/R-pkgs/bincraft /mnt/cache/R-pkgs/pkgcache /mnt/cache/pkgcache/R/pkgcache
-      - /opt/R/$R_VERSION/bin/R -q -e 'if (!requireNamespace("bincraft", quietly = TRUE) || packageVersion("bincraft") != "4.4.2") pak::pak("git::https://codefloe.com/rpkgs/bincraft.git@v4.4.2")'
+      - /opt/R/$R_VERSION/bin/Rscript local/install-bincraft.R
       - /opt/R/$R_VERSION/bin/R -q -e 'packageVersion("bincraft")'
       - mkdir -p /mnt/cache/pkgcache /mnt/cache/R-pkgs /mnt/cache/ccache /mnt/cache/packages
       # rhel-10 ships xwfb-run (Xwayland) instead of xvfb-run; prefer it and start weston, else fall back to xvfb-run
@@ -211,7 +211,7 @@ steps:
           echo "=== R-minor-sensitive update pass under R $RV ==="
           LIB="/mnt/cache/R-pkgs-$RMINOR"
           mkdir -p "$LIB"
-          R_LIBS_USER="$LIB" "$(dirname "$RBIN")/R" -q -e 'if (!requireNamespace("bincraft", quietly = TRUE) || packageVersion("bincraft") != "4.4.2") pak::pak("git::https://codefloe.com/rpkgs/bincraft.git@v4.4.2")' || true
+          R_LIBS_USER="$LIB" "$(dirname "$RBIN")/Rscript" local/install-bincraft.R || true
           R_LIBS_USER="$LIB" $XVFB $XVFB_ARGS -- "$(dirname "$RBIN")/R" -q -e "options(crayon.enabled = TRUE, Ncpus = 4, future.globals.onReference = NULL); bincraft::process_cran_updates(interval = $INTERVAL, platform = '${OS}', process_updated = TRUE, process_new = FALSE, process_removed = FALSE, patches = 'local/patches', r_minor_detection = 'classifier',r_minor_sensitive_only = TRUE, s3_endpoint = 'https://s3.eu-central-003.backblazeb2.com', s3_region = 'eu-central-003', s3_bucket = 'devxy-rpkgs-binaries', s3_access_key_id = Sys.getenv('B2_S3_ACCESS_KEY'), s3_secret_access_key = Sys.getenv('B2_S3_SECRET_KEY'), metadata_db_host = 'r-binaries.devxy.io', metadata_db_name = 'build_metadata', metadata_db_table = 'single_builds', metadata_db_user = 'rpkgs', metadata_db_password = Sys.getenv('PGPASS'), metadata_db_sslmode = 'require', metadata_db_port = 15432, archive = TRUE, upload = TRUE, store_build_metadata = TRUE)" || true
         done
       - /opt/R/$R_VERSION/bin/R -q -e 'library(bincraft); upload_package_index(codename = "${OS_ID}", s3_endpoint = "https://s3.eu-central-003.backblazeb2.com", s3_region = "eu-central-003", s3_bucket = "devxy-rpkgs-binaries", s3_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"), s3_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"))'