docs: add VIN Decoder listing copy and dns.md entry

Closes leeworks-agents/api-company#131
Closes leeworks-agents/api-company#130

- docs/rapidapi-listings.md: add Section 4 — VIN Decoder API with
  title, tagline, short/long description, tier table (Free/Basic/Pro/Ultra),
  endpoint descriptions, and keywords. Mirrors style of existing three
  API sections. Tiers match the spec from issue #131.
- docs/dns.md: add vin.leeworks.dev as 8th subdomain in records table,
  verification dig command, action-required count (7→8), and status
  checklist entry. Updated last-updated date to 2026-05-30.

docs/dns.md

@@ -1,6 +1,6 @@
 # DNS Configuration
 
-**Last updated:** 2026-05-24  
+**Last updated:** 2026-05-30  
 **Status:** Planned (Phase 6 pre-launch)
 
 ---
@@ -28,6 +28,7 @@ kubectl get svc -n ingress-nginx ingress-nginx-controller -o jsonpath='{.status.
 | `status.leeworks.dev` | A | `<cluster-ingress-ip>` | Gatus status page | Yes (cert-manager) |
 | `registry.leeworks.dev` | A | `<cluster-ingress-ip>` | Container registry (Gitea) | Yes (cert-manager) |
 | `grafana.leeworks.dev` | A | `<cluster-ingress-ip>` | Grafana (internal/restricted) | Yes (cert-manager) |
+| `vin.leeworks.dev` | A | `<cluster-ingress-ip>` | VIN Decoder API | Yes (cert-manager) |
 
 ---
 
@@ -103,6 +104,7 @@ dig docs.leeworks.dev +short
 dig status.leeworks.dev +short
 dig registry.leeworks.dev +short
 dig grafana.leeworks.dev +short
+dig vin.leeworks.dev +short
 
 # Check TLS certificates (once services are deployed)
 curl -v https://zip.leeworks.dev/health 2>&1 | grep -E "SSL|certificate|issuer"
@@ -126,7 +128,7 @@ The following actions require human operator access to the DNS provider:
 
 1. Log into the DNS provider managing `leeworks.dev`
 2. Find the cluster ingress IP: `kubectl get svc -n ingress-nginx ingress-nginx-controller`
-3. Create/update the 7 A records listed in the table above
+3. Create/update the 8 A records listed in the table above
 4. Verify propagation: `dig +trace zip.leeworks.dev`
 
 DNS propagation typically takes 5–60 minutes.
@@ -143,4 +145,5 @@ DNS propagation typically takes 5–60 minutes.
 - [ ] `status.leeworks.dev` → DNS record created
 - [ ] `registry.leeworks.dev` → DNS record created
 - [ ] `grafana.leeworks.dev` → DNS record created
-- [ ] TLS certificates issued and valid for all 7 subdomains
+- [ ] `vin.leeworks.dev` → DNS record created
+- [ ] TLS certificates issued and valid for all 8 subdomains

docs/rapidapi-listings.md

@@ -193,6 +193,77 @@ air quality, AQI, PM2.5, PM10, air pollution, smog, ozone, nitrogen dioxide, env
 
 ---
 
+---
+
+## 4. VIN Decoder API
+
+### API Name
+VIN Decoder API
+
+### Tagline
+Decode any vehicle VIN into make, model, year, engine, and trim — powered by NHTSA vPIC.
+
+### Short Description (≤ 300 chars)
+Decode any 17-character Vehicle Identification Number into structured vehicle data: make, model, year, trim, body style, engine specs, transmission, and assembly plant. Backed by the NHTSA vPIC public database with 90-day result caching.
+
+### Long Description
+
+Unlock the full story behind any Vehicle Identification Number with a single API call.
+
+**What you get per VIN:**
+- Make, model, model year, and trim level
+- Body class (Sedan, SUV, Pickup, etc.) and drive type (FWD, RWD, AWD, 4WD)
+- Engine displacement (CC and litres) and cylinder count
+- Primary fuel type (Gasoline, Diesel, Electric, Hybrid, etc.)
+- Transmission style (Automatic, Manual, CVT) and speed count
+- Assembly plant city, state, and country
+- Full manufacturer name and NHTSA vehicle type classification
+- NHTSA decode error code and text for non-standard VINs
+
+**Data source:** NHTSA Product Information Catalog and Vehicle Listing (vPIC) — US federal government public-domain data, always current. No licensing fees.
+
+**Coverage:** Model years 1981–present. All major domestic and import manufacturers registered with NHTSA.
+
+**Caching:** Decoded VINs are cached for 90 days in a local SQLite store. The `X-Cache: HIT/MISS` response header tells you whether the result came from cache or a live NHTSA lookup.
+
+**Use cases:**
+- Used-car marketplaces — enrich listings with decoded specs at scale
+- Insurance platforms — auto-populate vehicle details from VIN at quote time
+- Fleet management — maintain structured vehicle inventories without manual entry
+- Automotive valuation tools — feed year/make/model/trim into pricing algorithms
+- Recall & warranty systems — match VINs to manufacturer service campaigns
+- Registration & titling apps — validate and enrich VIN data in DMV workflows
+
+**Endpoints:**
+- `GET /v1/decode` — decode a single VIN
+- `POST /v1/batch` — decode up to 50 VINs in one request
+- `GET /v1/health` — service health check (no auth required)
+
+### Category
+Data / Automotive / Transportation
+
+### Plan Table
+
+| Tier | Price/month | Requests/month | Rate limit |
+|------|-------------|----------------|------------|
+| Free | $0 | 100 req/mo | 5 req/min |
+| Basic | $9 | 5,000 req/mo | 60 req/min |
+| Pro | $19 | 20,000 req/mo | 200 req/min |
+| Ultra | $49 | 100,000 req/mo | 500 req/min |
+
+### Endpoint Descriptions
+
+| Endpoint | Description |
+|----------|-------------|
+| `GET /v1/decode?vin={vin}` | Decodes a single 17-character VIN. Returns structured vehicle attributes including make, model, year, engine, body, drivetrain, and plant info. Optional `?raw=true` includes the full NHTSA vPIC response. |
+| `POST /v1/batch` | Accepts a JSON body with a `vins` array (1–50 VINs). Returns one decoded result (or error) per VIN in input order, plus aggregate counts for `cached_count` and `error_count`. |
+| `GET /v1/health` | Returns service status, uptime, cache stats (entries, hit rate, size), and NHTSA upstream reachability. No `X-RapidAPI-Proxy-Secret` required. |
+
+### Keywords
+VIN decoder, vehicle identification number, car lookup, NHTSA, make model year, automotive API, vehicle data, VIN lookup, auto specs, fleet management
+
+---
+
 ## Tagline Length Validation
 
 Run to confirm all taglines are ≤ 120 characters: