Add linting configuration for Markdown and YAML files

.gitattributes

@@ -0,0 +1 @@
+* text=auto eol=lf

.github/workflows/lint.yml

@@ -0,0 +1,23 @@
+name: Lint
+
+"on":
+  push:
+  pull_request:
+
+jobs:
+  markdownlint:
+    name: Markdown
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: DavidAnson/markdownlint-cli2-action@v19
+        with:
+          globs: "**/*.md"
+
+  yamllint:
+    name: YAML
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: pip install yamllint
+      - run: yamllint --format github .

.markdownlint.yaml

@@ -0,0 +1,8 @@
+default: true
+
+# Line length — relaxed to accommodate the ASCII circuit diagram
+# and table rows which can be naturally wide
+MD013:
+  line_length: 120
+  code_blocks: false  # don't enforce line length inside fenced code blocks
+  tables: false       # don't enforce line length inside tables

.yamllint.yaml

@@ -0,0 +1,11 @@
+extends: default
+
+ignore: |
+  .markdownlint.yaml
+
+rules:
+  line-length:
+    max: 120
+  truthy:
+    check-keys: false
+  document-start: disable

README.md

@@ -4,7 +4,8 @@
 
 PixelBrain32 is a personal ESP32-based controller for addressable LED strips, designed for use with ESPHome and Home Assistant.
 
-It's a small custom PCB that powers an ESP32 from the same 5 V supply as the LEDs, provides proper signal conditioning and level shifting for WS2812-style strips, and exposes a physical button for local control.
+It's a small custom PCB that powers an ESP32 from the same 5 V supply as the LEDs, provides proper signal conditioning
+and level shifting for WS2812-style strips, and exposes a physical button for local control.
 
 ---