Update docs, changelog, examples, and add ADRs for v1.2

- Add v1.1.0 and v1.2.0 changelog entries
- Add exclude field to config reference and example config
- Add ADRs documenting all major design decisions
- Fix step numbering in reverse_sync()
- Fix action.yml to copy VERSION file
- Add dist/ and .env to .gitignore
- Use refs/tags/ format for Nix flake tag refs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

action.yml

@@ -26,6 +26,7 @@ runs:
       run: |
         JOSH_DIR="$(mktemp -d)"
         cp -r "${{ github.action_path }}/bin" "${{ github.action_path }}/lib" "${JOSH_DIR}/"
+        cp "${{ github.action_path }}/VERSION" "${JOSH_DIR}/" 2>/dev/null || true
         chmod +x "${JOSH_DIR}/bin/josh-sync"
         echo "${JOSH_DIR}/bin" >> "$GITHUB_PATH"
         echo "JOSH_SYNC_ROOT=${JOSH_DIR}" >> "$GITHUB_ENV"