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>

docs/content/usage.md

@@ -0,0 +1,69 @@
+---
+title: CLI Reference
+weight: 20
+---
+
+## Common workflows
+
+```bash
+# Scaffold a default .releaser.yml
+releaser --init
+
+# Preview next version (no side effects)
+releaser --dry-run
+
+# Full release: bump versions, commit, tag, push, create release
+releaser
+
+# Commit and tag locally — skip push and release creation
+releaser --no-push
+
+# Push commit and tag but skip creating the release
+releaser --no-release
+
+# Update files but stop before committing
+releaser --no-commit
+# ... review changes, then commit manually and re-run:
+releaser --tag-only
+
+# Verbose mode: show config sources, commit analysis, version decision
+releaser --verbose --dry-run
+```
+
+## Flags
+
+| Flag | Default | Description |
+|------|---------|-------------|
+| `--dry-run` | false | Print next version and exit without making any changes |
+| `--branch <name>` | auto-detected | Override branch name (useful in detached HEAD / CI) |
+| `--branch-pattern <regex>` | `^(?:.*/)?release/(\d+)\.(\d+)$` | Override branch pattern (two capture groups: major, minor) |
+| `--tag-prefix <prefix>` | `""` | Prefix for version tags (e.g. `v` → `v1.2.3`) |
+| `--pom <path>` | `pom.xml` | Path to pom.xml relative to repo root |
+| `--changelog-file <path>` | `CHANGELOG.md` | Path to changelog file |
+| `--release-env-file <path>` | `release.env` | Path for dotenv artifact; pass `""` to disable |
+| `--no-commit` | false | Update version files but stop before committing |
+| `--no-push` | false | Commit and tag locally, skip push and release |
+| `--no-release` | false | Push branch and tag but skip release creation |
+| `--tag-only` | false | Skip version file updates — tag HEAD and push |
+| `--init` | false | Scaffold a default `.releaser.yml` and exit |
+| `--verbose` | false | Print config table, commit analysis, and version decision |
+
+## Exit codes
+
+| Code | Meaning |
+|------|---------|
+| `0` | Success |
+| `1` | Error (config, git, API, etc.) |
+| `2` | No releasable commits found — nothing to do |
+
+## Version bump rules
+
+By default all releasable commits bump the **patch** component (minor is pinned to the branch). Override per commit type via `git.bump_rules` in `.releaser.yml`:
+
+| Commit type | Default | Configurable via `bump_rules` |
+|-------------|---------|-------------------------------|
+| `fix:` | patch | `fix: "minor"` to bump minor |
+| `feat:` | patch | `feat: "minor"` to bump minor |
+| `feat!:` / `BREAKING CHANGE` | patch | `breaking: "minor"` to bump minor |
+| `chore:`, `docs:`, etc. | none | — |
+| unparseable message | none | non-strict: silently ignored |