Remove Cashu Access Token (CAT) system entirely (v0.52.3)

- Delete pkg/cashu/ package (BDHKE, issuer, verifier, keyset, token)
- Delete pkg/interfaces/cashu/ interface definitions
- Delete pkg/bunker/acl_adapter.go CAT authorization checker
- Delete app/handle-cashu.go HTTP handlers for mint endpoints
- Delete docs/NIP-XX-CASHU-ACCESS-TOKENS.md specification
- Remove Cashu config fields from app/config/config.go
- Remove CashuIssuer/CashuVerifier from app/server.go
- Remove CAT initialization and NRC Cashu verifier from app/main.go
- Remove token extraction from app/handle-websocket.go
- Remove CAT permission checks from app/handle-event.go
- Remove CashuEnabled from bunker info response
- Remove UseCashu field from NRC connections
- Remove AuthModeCAT from NRC protocol
- Remove CAT UI from BunkerView.svelte and RelayConnectView.svelte
- Remove cashu-client.js from web UI
- Add missing bunker worker stores to stores.js

Files modified:
- app/config/config.go: Removed Cashu config fields
- app/server.go: Removed Cashu issuer/verifier
- app/main.go: Removed Cashu initialization
- app/handle-*.go: Removed CAT checks and handlers
- app/listener.go: Removed cashuToken field
- pkg/database/nrc.go: Removed UseCashu field
- pkg/protocol/nrc/: Removed CAT auth mode and handling
- pkg/event/authorization/: Removed CAT import
- app/web/src/: Removed CAT UI components and logic
- main.go: Removed CAT help text

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

main.go

@@ -866,9 +866,6 @@ func printNRCUsage() {
 	fmt.Println("  ORLY_NRC_ENABLED=true")
 	fmt.Println("  ORLY_NRC_RENDEZVOUS_URL=wss://public-relay.example.com")
 	fmt.Println("  ORLY_NRC_AUTHORIZED_KEYS=<secret1>:<name1>,<secret2>:<name2>")
-	fmt.Println("")
-	fmt.Println("For CAT-based authentication, also set:")
-	fmt.Println("  ORLY_NRC_USE_CASHU=true")
 }
 
 // handleNRCGenerate generates a new NRC connection URI.
@@ -908,7 +905,7 @@ func handleNRCGenerate(ctx context.Context, cfg *config.C, args []string) {
 	}
 
 	// Get rendezvous URL from config
-	nrcEnabled, nrcRendezvousURL, _, _, _ := cfg.GetNRCConfigValues()
+	nrcEnabled, nrcRendezvousURL, _, _ := cfg.GetNRCConfigValues()
 	if !nrcEnabled || nrcRendezvousURL == "" {
 		fmt.Println("Error: NRC is not configured. Set ORLY_NRC_ENABLED=true and ORLY_NRC_RENDEZVOUS_URL")
 		return
@@ -950,7 +947,7 @@ func handleNRCGenerate(ctx context.Context, cfg *config.C, args []string) {
 
 // handleNRCList lists configured authorized secrets from environment.
 func handleNRCList(cfg *config.C) {
-	_, _, authorizedKeys, useCashu, _ := cfg.GetNRCConfigValues()
+	_, _, authorizedKeys, _ := cfg.GetNRCConfigValues()
 
 	fmt.Println("NRC Configuration:")
 	fmt.Println("")
@@ -977,8 +974,6 @@ func handleNRCList(cfg *config.C) {
 			fmt.Printf("  - %s: %s\n", name, truncated)
 		}
 	}
-	fmt.Println("")
-	fmt.Printf("  CAT authentication: %v\n", useCashu)
 }
 
 // handleNRCRevoke provides instructions for revoking access.