Skip Python CI on docs-only changes

Add paths-ignore (**.md, docs/**, mkdocs.yml) to ci.yml so lint/test/
build don't run when a change touches only prose (incl. a future mkdocs
site). Move the typos job to its own typos.yml with no path filter, so
spell-checking still runs on Markdown/docs changes.

Author: neuromechanist

.github/workflows/ci.yml

@@ -1,9 +1,20 @@
 name: CI
 
+# Python jobs (lint/test/build) skip when a change touches only prose --
+# Markdown or docs (incl. a future mkdocs site). Spell-checking lives in the
+# separate typos.yml, which has no such filter so docs are always checked.
 on:
   push:
     branches: [main]
+    paths-ignore:
+      - "**.md"
+      - "docs/**"
+      - "mkdocs.yml"
   pull_request:
+    paths-ignore:
+      - "**.md"
+      - "docs/**"
+      - "mkdocs.yml"
 
 concurrency:
   group: ci-${{ github.workflow }}-${{ github.ref }}
@@ -25,13 +36,6 @@ jobs:
       - name: ruff format --check
         run: uv run ruff format --check .
 
-  typos:
-    name: Typos
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: crate-ci/typos@v1
-
   test:
     name: Test (Python 3.12)
     needs: lint

.github/workflows/typos.yml

@@ -0,0 +1,17 @@
+name: Typos
+
+# Spell-check runs on every change (including Markdown/docs), so it is a
+# separate workflow from ci.yml, whose Python jobs skip prose-only changes.
+on: [push, pull_request]
+
+concurrency:
+  group: typos-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  typos:
+    name: Typos
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: crate-ci/typos@v1