feat: combine add-repo.sh and CI generator from #434 and #505

Replaces the script work of two prior PRs that independently solved
"add an existing scratchfoundation repo to the monorepo":

scripts/add-repo.sh — collapses add-to-monorepo.sh (#434) and add-repo.sh
(#505) into a single canonical entry point. Takes the CLI shape and
auto-CI-regen from #505 and the source-branch auto-detect (develop ->
main -> master), normalization (sort-package-json), and clean-tree
pre-flight from #434.

scripts/update-gha-workflows.ts — replaces the CircleCI-era
build-gha-workflows.ts and workspace-template.yml. Regenerates
.github/path-filters.yml and incrementally updates publish.yml.

Open review comments on #505 are addressed:

- sed -i portability bug: rewrites now use perl -pi -e (works on macOS,
  NixOS, Ubuntu/Debian/Arch, WSL). Perl is added to the explicit prereq
  check next to git-filter-repo, sponge, and jq.
- Arg parser now rejects flag-stealing: --source-branch --org foo errors
  instead of silently using --org as the branch name.
- npm-install failures hard-fail by default. --continue-on-error opts
  into the prior soft-fail behavior; failures are still logged to
  add-repo.errors.log when continuing. Scoped to per-dep package.json
  rewrite failures in the rewire step; the final lockfile install
  always hard-fails by design.
- The submodules-aware branch in move_repository_subdirectory keeps a
  TODO comment marking that it has never been exercised against a real
  submodules-bearing repo and should be run carefully when one lands.

Cross-workspace dep handling: rewires both bare-name and already-prefixed
@scratch/<name> deps in the new package to exact-pinned current monorepo
versions. Matches the existing convention in scratch-gui/scratch-vm/
scratch-render. npm's workspace: protocol would be the ideal here but
npm does not actually support it (npm/cli#8845 - EUNSUPPORTEDPROTOCOL
at install time).

Workspaces array ordering: the new package is inserted just after the
latest existing workspace it depends on, so 'npm run --workspaces build'
builds its deps first. Falls back to position 0 (prepend) when the new
package has no monorepo deps. This is a "last dep wins" heuristic, not
a full topological sort; it relies on the existing workspaces array
already being in valid build order. A real topo sort can be added later
(e.g. by extending update-gha-workflows.ts) if it ever becomes necessary.

bash 3.2 compatibility: macOS ships bash 3.2 at /bin/bash, which lacks
the 'mapfile' builtin. The find/grep output is collected via a 'while
IFS= read -r' loop so the script runs on macOS as well as Linux.

Bare-clone alternates path: bare clones store the alternates file at
objects/info/alternates, not .git/objects/info/alternates. The previous
path was a no-op; the working disconnection comes from --dissociate in
the clone command. Path corrected so the line is defensive belt-and-
braces rather than dead code.

update-gha-workflows.ts: throws with a clear error if npm query returns
a workspace not present in the root "workspaces" array (previously
would silently misorder via indexOf returning -1). The comment in
resolveWorkspaces is corrected to reflect that the function returns
Map insertion order, with the caller re-sorting into declared order.
The npm query exec call now requests a 64 MiB maxBuffer; Node's
default 1 MiB is fine for the current repo size but would silently
truncate as the monorepo grows.

Path anchoring: BUILD_TMP, BUILD_CACHE, and any user-supplied
--cache-dir value are resolved to absolute paths up front. A
CWD-relative default would have put add-repo.tmp outside the repo
(and outside the .gitignore pattern) if the script were run from a
subdirectory of the monorepo.

No repo additions are included; this PR is script-tooling only.

Author: cwillisf

.github/path-filters.yml

@@ -1,3 +1,7 @@
+# This file is generated by scripts/update-gha-workflows.ts
+#
+# To regenerate:  npm run refresh-gh-workflow
+
 # The `&global` anchor defines a set of common paths to include by reference in the other filters.
 global: &global
   - ".github/path-filters.yml"
@@ -14,9 +18,6 @@ any-workspace:
 task-herder:
   - *global
   - "packages/task-herder/**"
-scratch-media-lib-scripts:
-  - *global
-  - "packages/scratch-media-lib-scripts/**"
 scratch-svg-renderer:
   - *global
   - "packages/scratch-svg-renderer/**"
@@ -35,3 +36,6 @@ scratch-gui:
   - "packages/scratch-render/**"
   - "packages/scratch-svg-renderer/**"
   - "packages/scratch-vm/**"
+scratch-media-lib-scripts:
+  - *global
+  - "packages/scratch-media-lib-scripts/**"

.gitignore

@@ -1,7 +1,6 @@
-# build-monorepo.sh
-/monorepo.out
-/monorepo.tmp
-/monorepo.cache
+# add-repo.sh
+/add-repo.tmp
+/add-repo.errors.log
 
 # Logs
 logs

package.json

@@ -24,10 +24,9 @@
   ],
   "scripts": {
     "build": "cross-env NODE_ENV=production npm run --workspaces build",
-    "build-monorepo": "cross-env-shell ./scripts/build-monorepo.sh",
     "clean": "npm run --workspaces clean",
     "prepare": "husky install",
-    "refresh-gh-workflow": "ts-node scripts/build-gha-workflows.ts",
+    "refresh-gh-workflow": "ts-node scripts/update-gha-workflows.ts",
     "start": "npm --workspace @scratch/scratch-gui start",
     "test": "npm test --workspaces",
     "update-legal": "npm --workspaces exec -c 'rm -f ./{LICENSE,TRADEMARK} && cp -f ../../{LICENSE,TRADEMARK} .'",