Add lychee link-check recipes to justfile

CONTRIBUTING.md

@@ -28,6 +28,16 @@ uv sync --group docs
 make docs
 ```
 
+### Checking links
+
+A full doc render takes minutes. To validate links faster, install [lychee](https://lychee.cli.rs/) (`brew install lychee`, `cargo install lychee`, or grab a binary from the [releases page](https://github.com/lycheeverse/lychee/releases)), then:
+
+```bash
+just linkcheck         # .qmd sources, offline (no render needed)
+just linkcheck-site    # render with --no-execute, then check rendered HTML (catches quartodoc cross-refs and anchors)
+just linkcheck-online  # .qmd sources + external URLs
+```
+
 ## Running specific tests
 
 ```bash

justfile

@@ -42,6 +42,27 @@ docs:
     cd docs; uv run quartodoc build; uv run quarto render
     if (!(Test-Path docs/_site/index.html)) { Write-Error "Error: index.html not found."; exit 1 }
 
+# Build docs without executing Python (fast; produces a link-checkable _site/)
+[unix]
+docs-fast:
+    cd docs && uv run quartodoc build && uv run quarto render --no-execute
+
+[windows]
+docs-fast:
+    cd docs; uv run quartodoc build; uv run quarto render --no-execute
+
+# Check links in .qmd sources (offline, no render needed)
+linkcheck:
+    lychee --offline --include-fragments 'docs/**/*.qmd'
+
+# Check links in rendered site (catches quartodoc cross-refs and anchors)
+linkcheck-site: docs-fast
+    lychee --offline --include-fragments 'docs/_site/**/*.html'
+
+# Check external URLs in .qmd sources (hits the network)
+linkcheck-online:
+    lychee --include-fragments 'docs/**/*.qmd'
+
 # Clean build artifacts
 [unix]
 clean: