cli: etchy log — per-commit layer changes over a git range

CHANGELOG.md

@@ -11,6 +11,10 @@ Cut a new section here as part of tagging a release — see "Cutting a release"
 
 ### Added
 - Viewer change navigator with per-layer region lists, X2 labels, framing, highlight, and rebindable N/P keys (#419).
+- `etchy log <range> [subdir]` lists, per commit in a git range that touches the
+  fab pack, which layers changed and by how much (area, regions), in summary,
+  Markdown and JSON. Each commit is diffed against its first parent, no checkout.
+  `--max-commits` (default 200) fails loud instead of truncating (#424).
 
 ### Fixed
 - A drill or placement file that fails to parse is no longer reported as

README.md

@@ -57,6 +57,14 @@ add the Action to a repo (full recipe in
 The job grants `pull-requests: write`; etchy supplies its own token and posts a
 sticky per-layer table (added / removed mm² and region counts).
 
+**History over a git range** — `etchy log` walks the commits that touch the fab
+pack and prints, per commit, which layers changed and by how much (no checkout;
+`--format md|json` too; exit 1 if any commit changed a layer):
+
+```sh
+etchy log v0.1.0..HEAD fab/   # newest first, each commit vs its first parent
+```
+
 **PDF diff** — schematic PDFs get a page-by-page pixel diff (builds with
 `--features pdf`; release binaries ship it on):