docs(releaser): release v1.5.1 — documentation site, fuzzing completeness

- Add Hugo + Geekdoc documentation site (docs/): installation, CLI
  reference, configuration, CI integration, and changelog pages; explicit
  menu bundle nav so all pages appear in the sidebar on every page
- Add Gitea CI workflow (.gitea/workflows/docs.yml): builds on push to
  main when docs/** changes, deploys minified site to gh-pages branch
- Add docs:setup / docs:serve / docs:build Taskfile tasks; theme bundle
  downloaded at build time (not committed)
- Add FuzzUpdate to internal/changelog and FuzzWriteVersion to
  internal/node to complete fuzz coverage for all file-rewriting packages
- Add fuzzing completeness guidelines to CLAUDE.md: authoritative table,
  exempt-package rationale, seed corpus rules

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

ROADMAP.md

@@ -74,7 +74,7 @@
 - [x] ~~GitHub release support~~ — ✓ shipped v1.4.0 (`internal/ghclient`, `GITHUB_TOKEN` env, `github.token`/`github.repo` config; GitHub takes precedence over GitLab)
 - [x] ~~SSH agent push~~ — ✓ shipped v1.4.0 (go-git `gitssh.NewSSHAgentAuth` for `git@`/`ssh://` remotes)
 - [x] ~~Configurable bump rules~~ — ✓ shipped v1.4.0 (`git.releasable_types` config; filter which commit types trigger a release)
-- [ ] Documentation site
+- [x] ~~Documentation site~~ — ✓ shipped v1.5.1 (Hugo + Geekdoc; installation, CLI reference, configuration, CI integration pages; deployed via Gitea CI to `gh-pages`)
 
 ## v1.5 — Multi-module, Node.js, configurable bump rules ✅
 
@@ -87,4 +87,3 @@
 
 - Gradle support (`build.gradle` / `build.gradle.kts`)
 - Slack / Teams notification on release
-- Documentation site