docs: end-to-end gardening — links, stale refs, tailscale.md update

Comprehensive documentation gardening across the merged repo:

- tailscale.md: fully rewritten with current ground truth. The netinfra
  pair now runs production Technitium with all knel.net records
  replicated. Both LAN IPs resolve knel.net device names and recurse
  externally. The old "NXDOMAIN / zone is stale" findings are replaced
  with the resolved state and current recommendations.
- AGENTS.md: rewritten with Gitea-compatible clickable relative links
  to all key scripts and docs. Autonomous commit/push policy
  prominently documented. SSH user corrected to localuser.
- README.md: directory table and docs table now use clickable links.
- All .md cross-references converted to Gitea-renderable relative links.
- Stale path references (ProjectCode/, Project-Tests/, ProjectDocs/)
  updated to current names (provisioning/, tests/) across all docs.
- Stale repo name "FetchApply" / "KNELServerBuild" updated to
  "PFVCluster" in actionable docs; historical AI-review docs tagged
  with an HTML comment notice.
- REFACTORING-EXAMPLES.md: tagged as historical (pre-refactor patterns).
- tests/README.md, dns-cluster-setup/README.md, docs/DEPLOYMENT.md,
  docs/SECURITY.md: path references fixed to current structure.

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docs/DEPLOYMENT.md

@@ -77,7 +77,7 @@ git clone [repository-url]
 cd FetchApply
 
 # 2. Review configuration
-cat ProjectCode/SetupNewSystem.sh
+cat provisioning/SetupNewSystem.sh
 
 # 3. Execute with manual review
 cd ProjectCode
@@ -256,7 +256,7 @@ cd FetchApply
 git pull origin main
 
 # Re-run specific modules
-cd ProjectCode/Modules/Security
+cd provisioning/Modules/Security
 sudo bash secharden-ssh.sh
 ```
 
@@ -291,7 +291,7 @@ sudo bash secharden-ssh.sh
 ### Documentation
 - **README.md:** Basic usage instructions
 - **SECURITY.md:** Security architecture and guidelines
-- **Project-Tests/README.md:** Testing framework documentation
+- **tests/README.md:** Testing framework documentation
 
 ### Community Support
 - **Issues:** https://projects.knownelement.com/project/reachableceo-vptechnicaloperations/timeline