docs: add TLD registrar model (Option B) to name registration plan

One constant change makes ALL names require authority signature.
Eliminates the 90K pre-registration race entirely. Lethean becomes
a proper TLD registrar for .lthn — curated namespace, revenue from
name sales, squatting impossible at protocol level.

Co-Authored-By: Charon <charon@lethean.io>

PLAN-NAME-REGISTRATION.md

@@ -126,6 +126,68 @@ bash tools/register-reserved.sh /tmp/protected-names-long.txt http://127.0.0.1:4
 
 Tool location: `docker/tools/register-reserved.sh`
 
+## Option B: TLD Registrar Model (Recommended)
+
+Instead of racing to pre-register 90K names, change one constant to make
+ALL alias registration require the authority key:
+
+```c
+// currency_config.h — one line change
+#define ALIAS_MINIMUM_PUBLIC_SHORT_NAME_ALLOWED  64  // was 6
+```
+
+This makes Lethean a proper TLD registrar — every name under `.lthn`
+requires authority signature. No squatting possible at any length.
+
+### Why This Is Better
+
+| Pre-reg (Option A) | Registrar (Option B) |
+|---------------------|----------------------|
+| Race against squatters | No race — authority controls all |
+| 90K transactions needed | Zero pre-registration needed |
+| ~90K LTHN cost | Zero cost |
+| Only covers known names | Covers ALL names, forever |
+| New brands unprotected | New brands protected by default |
+
+### Registrar Portal Flow
+
+1. User requests `@myname` via website or CLI
+2. Portal checks: not taken, not reserved, not offensive
+3. User pays registration fee (1 LTHN + portal fee if desired)
+4. Authority key signs the registration transaction
+5. Name goes live on chain within 1 block
+
+### Revenue Potential
+
+| Name Type | Price |
+|-----------|-------|
+| Standard (6+ chars) | 1 LTHN (chain fee only) |
+| Short (3-5 chars) | 10-100 LTHN (premium) |
+| Ultra-short (1-2 chars) | Auction or reserved |
+
+### Implementation
+
+- **Hardfork:** Change `ALIAS_MINIMUM_PUBLIC_SHORT_NAME_ALLOWED` to 64
+- **Portal:** Web API that accepts requests, validates, signs with authority key
+- **Key security:** Authority private key in HSM or multi-sig, never on a hot server
+- **Delegation:** Portal signs, daemon validates — separation of concerns
+
+### Why Lethean Should Be a Registrar
+
+- Lethean owns `.lthn` on Handshake — it IS the TLD operator
+- Names route real traffic (VPN, DNS, service discovery)
+- A curated namespace is trustworthy; a squatted one is worthless
+- Every TLD in the world works this way — `.com`, `.co.uk`, `.eth`
+- Revenue stream from name sales funds network development
+
+### Migration Path
+
+1. Testnet: validate both approaches (pre-reg + registrar)
+2. HF proposal: include the constant change in next hardfork
+3. Build portal: simple web UI + authority signing service
+4. Mainnet launch: registrar model active from HF activation
+5. Pre-reg only needed for names registered BEFORE the HF
+
 ## Risk Mitigations
 
 | Risk | Mitigation |