## Summary
Builds R-minor-sensitive CRAN packages once per installed R minor version (into per-minor S3 slots `…/contrib/<x.y>/`) and everything else once into the generic slot, driven by bincraft 4.2.0's ABI classifier. Both the full and iterative pipelines are covered.
## What's in here
**Detection / precompute**
- `local/r-minor-helpers.R` — pure `classify_from_metadata()` (NeedsCompilation / risky `LinkingTo`) + `parse_build_args()`, with unit tests.
- `local/packages-to-build.R` — adds a per-package `r_minor_sensitive` flag: cheap CRAN-metadata rules first, source download + `bincraft::needs_per_minor_recompile()` only for the ambiguous compiled subset (fail-safe to sensitive). Classified once per package, applied to all versions.
**Full build**
- `local/build-all.R` — passes the per-row `is_r_minor_sensitive` flag; new `--sensitive-only` mode builds just the risky subset.
- `.crow/build-all-versions-{amd64,arm64}.yaml` — install-deps persists the sensitive subset; build step runs a sensitive-only pass under each non-primary `/opt/R/*` minor; new step uploads the generic index plus a per-minor index for each minor.
**Iterative build**
- All 14 `.crow/process-updates-*.yaml` — primary pass uses `r_minor_detection = 'classifier'`; a sensitive-only multi-R pass builds risky updates under each other minor; per-minor index upload added.
**Tooling / housekeeping**
- Pins bincraft `v4.1.1` → `v4.2.0` across all workflows; removes the superseded standalone `build-r-minor-sensitive-packages.yaml`.
- Adds prek/pre-commit hooks (prettier, markdownlint, editorconfig-checker, yamllint, air) and applies them repo-wide; excludes the verbatim GPL `LICENSE.md` and auxiliary shell scripts.
- Design + implementation docs under `docs/superpowers/`.
## Requires before merge
- A `v4.2.0` git tag must be pushed on the bincraft repo (codefloe.com/rpkgs/bincraft) — the workflow install steps pin `@v4.2.0`. The full-build install-deps clones `main`, so it is unaffected.
Reviewed-on: #84
s3fs uses reticulate/Python which significantly increases R process memory.
When pak tries to fork R to install package dependencies, the enlarged
process can't be duplicated within the container memory limit.
Now the install-deps step saves the S3 file listing as s3_cache.rds,
and the build step reads it with readRDS() — no s3fs loading needed.
The precompute script was constructing S3 paths as "redhat10" while
bincraft uses "rhel10" as the codename. This mismatch caused the
precompute to find no existing packages in S3, producing ~77K false
positive package versions that all get skipped at build time.
Now uses bincraft::set_codename() to ensure path alignment.
Also fixes nrow() vs length() in install-deps summary message.
packages-to-build.R now saves the full (Package, Version) data.table
so the build step can pass specific tags to build_binary_package(),
eliminating redundant per-package tag discovery and S3 checks.
Also reduces archive versions from 9 to 4 (+ 1 release = 5 total).
The S3 credentials, endpoint, and bucket name were still pointing to the old Hetzner storage after the Backblaze migration, causing silent build failures.
