refactor: single source of truth for excluded packages (#79)

## Summary

`local/build-all.R` had a 75-name hardcoded `exclude <- c(...)` vector that had drifted from `local/excluded-packages.json` — `RcmdrPlugin.ROC` was in the R vector but missing from the JSON.

`.crow/weekly-rebuild-missing-*.yaml` already reads the JSON via `jsonlite::fromJSON(...)[["package"]]`. This brings `build-all.R` in line with that pattern.

Changes:

- **`local/excluded-packages.json`**: add the missing `RcmdrPlugin.ROC` entry (reason `"hang"`, matching siblings).
- **`local/build-all.R`**: replace the 16-line hardcoded vector with one `jsonlite::fromJSON(...)` call.
- **`.crow/build-all-versions-install-deps-{amd,arm}64.yaml`**: add `jsonlite` to the install-deps `pak::pak()` list so it's available in `/mnt/cache/R-pkgs` for the build step.
- **`.crow/build-all-versions-arm64.yaml`**: drop the dead base64-encoded `SKIP_PKGS` docs comment that nobody was passing as a `--var` anyway; replace with a one-line pointer to the JSON.

Reviewed-on: #79

local/build-all.R

@@ -21,23 +21,8 @@ chunks <- split(pkgs, cut(seq_len(nrow(pkgs)), split_into, labels = FALSE))
 chunk <- chunks[[split_index]]
 sprintf("# of package versions for this job: %s", nrow(chunk))
 
-# Exclude known problematic packages
-exclude <- c(
-  "RInno", "KeyboardSimulator", "R2PPT", "RWinEdt", "blatr", "excel.link",
-  "spectrino", "taskscheduleR", "MDSGUI", "BiplotGUI", "R2wd", "rFUSION",
-  "MediaNews", "doBy", "IDPmisc", "frailtypack", "afex", "FrF2", "DoE.base",
-  "agricolae", "doFuture", "fscaret", "PHYLOGR", "seewave", "pls", "relaimpo",
-  "geepack", "gggenes", "NPCirc", "repmis", "PNDSIBGE", "lidR", "poismf",
-  "neonstore", "MachineShop", "mvst", "MacBehaviour", "mcmcderive", "RGIFT",
-  "KnowBR", "netmeta", "spdep", "Rfast", "compareGroups", "ff", "GsymPoint",
-  "RcppDynProg", "comtradr", "FD", "PearsonDS", "DCluster", "gRc", "mixlm",
-  "geospt", "fdth", "ffmanova", "fiery", "ffscrapr", "cold",
-  "RcmdrPlugin.DoE", "RcmdrPlugin.NMBU", "RcmdrPlugin.RiskDemo",
-  "RcmdrPlugin.ROC", "RcmdrPlugin.TeachStat", "RcmdrPlugin.TeachingDemos",
-  "RcmdrPlugin.UCA", "RcmdrPlugin.WorldFlora", "RcmdrPlugin.aRnova",
-  "RcmdrPlugin.depthTools", "RcmdrPlugin.orloca", "RcmdrPlugin.sos",
-  "RcmdrPlugin.survival", "RcmdrPlugin.temis", "GWlasso", "GWmodelVis"
-)
+# Exclude known problematic packages (single source of truth)
+exclude <- jsonlite::fromJSON("local/excluded-packages.json")[["package"]]
 chunk <- chunk[!chunk$Package %in% exclude, ]
 
 # Read pre-computed S3 listing from install-deps step

local/excluded-packages.json

@@ -61,6 +61,7 @@
   {"package": "RcmdrPlugin.DoE", "reason": "hang"},
   {"package": "RcmdrPlugin.NMBU", "reason": "hang"},
   {"package": "RcmdrPlugin.RiskDemo", "reason": "hang"},
+  {"package": "RcmdrPlugin.ROC", "reason": "hang"},
   {"package": "RcmdrPlugin.TeachStat", "reason": "hang"},
   {"package": "RcmdrPlugin.TeachingDemos", "reason": "hang"},
   {"package": "RcmdrPlugin.UCA", "reason": "hang"},