Air-gap fixes + in-app /docs (README/DEPLOYMENT/api.md/docs/*)

Air-gap:
- DynamicRecord.refreshAll() called getPublicIp() (api.ipify.org,
  icanhazip.com, ifconfig.me) every 4h on a timer regardless of
  whether any dynamic records were configured -- the one background
  call in the repo not actually gated by feature use. Now skips the
  lookup entirely when there's nothing to refresh.
- Removed the stray, unauthenticated GET /test page (a leftover
  jq-repeat demo) that loaded jQuery + Mustache from external CDNs.
- Removed a dead IE<9-only html5shim script tag pointing at a domain
  that no longer resolves.

Docs:
- New GET /docs (index) and /docs/:slug routes render this project's
  own README, DEPLOYMENT, api.md, and docs/*.md server-side via
  marked (new dependency) -- so the documentation is readable from
  the running app with no route to GitHub Pages, where it otherwise
  only lives. Public, no auth, same tier as the health endpoint.
- .dockerignore/Dockerfile updated: docs/, DEPLOYMENT.md, and
  nodejs/api.md were previously excluded from the image entirely
  ("served via GitHub Pages, not from the image") -- now copied in
  alongside README.md/tos.md-style, since they're needed at runtime.

nodejs/models/dynamic_record.js

@@ -76,8 +76,17 @@ class DynamicRecord extends Table{
 		}
 	}
 
-	// Resolve the public IP once, then reconcile every record to it.
+	// Resolve the public IP once, then reconcile every record to it. Checked
+	// BEFORE the public-IP lookup: on a stock install with zero dynamic
+	// records configured, this runs on a timer regardless (services/dynamic_dns.js)
+	// -- without this guard it would still reach out to the public-IP
+	// resolvers (utils/public_ip.js) every cycle for nothing, which is
+	// exactly the kind of always-on external call an air-gapped deployment
+	// can't have.
 	static async refreshAll(){
+		let records = await this.listDetail();
+		if(!records.length) return {count: 0};
+
 		let ip;
 		try{
 			ip = await getPublicIp();
@@ -86,7 +95,6 @@ class DynamicRecord extends Table{
 			return {error: error.message};
 		}
 
-		let records = await this.listDetail();
 		for(let record of records){
 			await record.apply(ip);
 		}