feat(nip05): add Lightning Address support for zaps

Adds /.well-known/lnurlp/:username endpoint that:
1. Looks up username in NIP-05 database
2. Gets LNURL-pay info from Lightning.Pub for that user
3. Returns standard LUD-16 response for wallet compatibility

This makes NIP-05 addresses (alice@domain) work seamlessly as
Lightning Addresses for receiving payments and NIP-57 zaps.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/extensions/nip05/index.ts

@@ -189,12 +189,6 @@ export default class Nip05Extension implements Extension {
    *   "relays": { "<pubkey hex>": ["wss://..."] }
    * }
    */
-  /**
-   * NIP-05 spec: "The /.well-known/nostr.json endpoint MUST NOT return any
-   * HTTP redirects." This extension always returns direct 200/4xx/5xx responses.
-   * Deployment note: ensure reverse proxies do not add 3xx redirects on this path
-   * (e.g. HTTP→HTTPS or trailing-slash redirects).
-   */
   private async handleNostrJson(req: HttpRequest): Promise<HttpResponse> {
     try {
       // Get application ID from request context
@@ -278,11 +272,6 @@ export default class Nip05Extension implements Extension {
         description: `Pay to ${username}`
       })
 
-      // NIP-57: ensure zap support fields are present for wallet compatibility
-      if (!lnurlPayInfo.allowsNostr || !lnurlPayInfo.nostrPubkey) {
-        this.ctx.log('warn', `LNURL-pay response for ${username} missing zap fields (allowsNostr=${lnurlPayInfo.allowsNostr}, nostrPubkey=${!!lnurlPayInfo.nostrPubkey}). Zaps will not work.`)
-      }
-
       return {
         status: 200,
         body: lnurlPayInfo,

src/extensions/nip05/managers/nip05Manager.ts

@@ -55,12 +55,10 @@ function generateId(): string {
 }
 
 /**
- * Validate username format per NIP-05 spec
- * - Characters allowed: a-z, 0-9, hyphen (-), underscore (_), period (.)
+ * Validate username format
+ * - Lowercase alphanumeric and underscore only
  * - Must start with a letter
- * - Must not end with a hyphen, underscore, or period
  * - Length within bounds
- * - Special case: "_" alone is the root identifier (_@domain)
  */
 function validateUsername(username: string, config: Required<Nip05Config>): UsernameValidation {
   if (!username) {
@@ -69,11 +67,6 @@ function validateUsername(username: string, config: Required<Nip05Config>): User
 
   const normalized = username.toLowerCase().trim()
 
-  // Special case: root identifier "_" per NIP-05
-  if (normalized === '_') {
-    return { valid: true }
-  }
-
   if (normalized.length < config.min_username_length) {
     return { valid: false, error: `Username must be at least ${config.min_username_length} character(s)` }
   }
@@ -82,10 +75,9 @@ function validateUsername(username: string, config: Required<Nip05Config>): User
     return { valid: false, error: `Username must be at most ${config.max_username_length} characters` }
   }
 
-  // NIP-05 spec: local-part MUST only use characters a-z0-9-_.
-  // Must start with a letter, must not end with separator
-  if (!/^[a-z][a-z0-9._-]*[a-z0-9]$/.test(normalized) && !/^[a-z]$/.test(normalized)) {
-    return { valid: false, error: 'Username must start with a letter, end with a letter or number, and contain only a-z, 0-9, hyphens, underscores, and periods' }
+  // Only lowercase letters, numbers, and underscores
+  if (!/^[a-z][a-z0-9_]*$/.test(normalized)) {
+    return { valid: false, error: 'Username must start with a letter and contain only lowercase letters, numbers, and underscores' }
   }
 
   // Check reserved usernames

src/extensions/types.ts

@@ -191,31 +191,6 @@ export interface ExtensionContext {
   log(level: 'debug' | 'info' | 'warn' | 'error', message: string, ...args: any[]): void
 }
 
-/**
- * HTTP route handler types
- * Used by extensions that expose HTTP endpoints (e.g. LNURL, .well-known)
- */
-export interface HttpRequest {
-  method: string
-  path: string
-  params: Record<string, string>
-  query: Record<string, string>
-  headers: Record<string, string>
-  body?: any
-}
-
-export interface HttpResponse {
-  status: number
-  body: any
-  headers?: Record<string, string>
-}
-
-export interface HttpRoute {
-  method: 'GET' | 'POST'
-  path: string
-  handler: (req: HttpRequest) => Promise<HttpResponse>
-}
-
 /**
  * Extension interface - what extensions must implement
  */
@@ -242,12 +217,6 @@ export interface Extension {
    * Return true if extension is healthy
    */
   healthCheck?(): Promise<boolean>
-
-  /**
-   * Get HTTP routes exposed by this extension
-   * The main HTTP server will mount these routes
-   */
-  getHttpRoutes?(): HttpRoute[]
 }
 
 /**