feat: R-minor-sensitive binary builds (full + iterative) (#84)

## 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- Pins bincraft `v4.1.1` → `v4.2.0` across all workflows; removes the superseded standalone `build-r-minor-sensitive-packages.yaml`.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

local/build-all.R

@@ -1,10 +1,13 @@
 sink(stdout(), type = "message")
 options(crayon.enabled = TRUE, future.globals.onReference = NULL)
+source(file.path("local", "r-minor-helpers.R"))
 
 args <- commandArgs(trailingOnly = TRUE)
-split_into <- as.integer(args[1])
-split_index <- as.integer(args[2])
-ncpus <- as.integer(args[3])
+parsed <- parse_build_args(args)
+split_into <- parsed$split_into
+split_index <- parsed$split_index
+ncpus <- parsed$ncpus
+sensitive_only <- parsed$sensitive_only
 options(Ncpus = ncpus)
 
 # Load bincraft eagerly to avoid lazy-load memory spike during first build call
@@ -12,9 +15,20 @@ library(bincraft, quietly = TRUE)
 library(future)
 plan("sequential")
 
-# Read precomputed package+version pairs
-pkgs <- readRDS("/mnt/cache/packages/pkgs_to_build.rds")
-sprintf("Total# of remaining package versions: %s", nrow(pkgs))
+pkgs <- if (sensitive_only) {
+  readRDS("/mnt/cache/packages/r_minor_sensitive_pkgs.rds")
+} else {
+  readRDS("/mnt/cache/packages/pkgs_to_build.rds")
+}
+# Back-compat: tolerate an older RDS without the column (treat all as non-sensitive)
+if (is.null(pkgs$r_minor_sensitive)) {
+  pkgs$r_minor_sensitive <- FALSE
+}
+sprintf(
+  "Total# of remaining package versions: %s (sensitive_only=%s)",
+  nrow(pkgs),
+  sensitive_only
+)
 
 # Split into chunks for this worker
 chunks <- split(pkgs, cut(seq_len(nrow(pkgs)), split_into, labels = FALSE))
@@ -32,26 +46,33 @@ s3_cache <- readRDS("/mnt/cache/packages/s3_cache.rds")
 sprintf("S3 cache: %s files", length(s3_cache))
 
 n <- nrow(chunk)
-mapply(function(pkg, ver, i) {
-  cat(sprintf("[%d/%d] %s_%s\n", i, n, pkg, ver))
-  bincraft::build_binary_package(
-    pkg,
-    tag = ver,
-    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"),
-    s3_package_cache = s3_cache,
-    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
-  )
-}, chunk$Package, chunk$Version, seq_len(n))
+mapply(
+  function(pkg, ver, sens, i) {
+    cat(sprintf("[%d/%d] %s_%s (r_minor_sensitive=%s)\n", i, n, pkg, ver, sens))
+    bincraft::build_binary_package(
+      pkg,
+      tag = ver,
+      is_r_minor_sensitive = isTRUE(sens),
+      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"),
+      s3_package_cache = s3_cache,
+      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
+    )
+  },
+  chunk$Package,
+  chunk$Version,
+  chunk$r_minor_sensitive,
+  seq_len(n)
+)