Add doc-random task and documentation improvements (#98)

## Summary
- Add `doc-random` mise task that selects a random documentation card for review
- Add how-to/knowledgebase section with review-documentation guide
- Add Caddy reference card with proxy configuration details
- Fix replication tutorial sequence (tailscale-setup now links to core-services)
- Fix "BluemeOps" typo in tailscale-setup
- Clean up obsolete zk/ directory references from doc-links

## Deployment and Testing
- [x] `mise run doc-random` works and displays a random card
- [x] `mise run doc-links` passes (all wiki-links valid)
- [x] Pre-commit hooks pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: https://forge.ops.eblu.me/eblume/blumeops/pulls/98

docs/tutorials/ai-assistance-guide.md

@@ -88,6 +88,7 @@ BlumeOps operations are driven by mise tasks. Run `mise tasks` to list all avail
 | `doc-links` | Validate wiki-links in documentation |
 | `doc-titles` | Check for duplicate doc titles |
 | `doc-filenames` | Check for duplicate doc filenames |
+| `doc-random` | Select a random doc card for review |
 | `indri-runner-logs` | View Forgejo workflow logs from local runner |
 
 For ArgoCD operations, use the `argocd` CLI directly: