Update JWT documentation for new database interface

Updated all examples to reflect the simplified database API that uses
*sql.DB and *sql.Tx directly instead of custom wrapper interfaces.

Changes:
- Changed GeneratorConfig.DBConn to GeneratorConfig.DB (*sql.DB)
- Updated all transaction examples to use db.Begin() directly
- Removed references to jwt.NewDBConnection() wrapper
- Fixed GORM example to show correct usage with sqlDB
- Corrected Bun example - sql.DB should be created first, then passed
  to both Bun and JWT generator (previously showed incorrect usage)
- Updated complete example with proper transaction handling
- Simplified API makes it clearer how to integrate with ORMs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

JWT.md

@@ -47,7 +47,7 @@ func main() {
         FreshExpireAfter:   5,    // Tokens stay fresh for 5 minutes
         TrustedHost:        "example.com",
         SecretKey:          "your-secret-key-here",
-        DBConn:             jwt.NewDBConnection(db),
+        DB:                 db,
         DBType: jwt.DatabaseType{
             Type:    jwt.DatabasePostgreSQL,
             Version: "15",
@@ -92,7 +92,7 @@ type GeneratorConfig struct {
     SecretKey          string // Secret key for token signing
 
     // Optional fields (for database support)
-    DBConn      DBConnection  // Database connection (nil to disable revocation)
+    DB          *sql.DB       // Database connection (nil to disable revocation)
     DBType      DatabaseType  // Database type and version
     TableConfig TableConfig   // Table configuration
 }
@@ -162,10 +162,8 @@ token, expiry, err := gen.NewRefresh(42, true)
 Tokens must be validated within a transaction context:
 
 ```go
-import "context"
-
 // Begin transaction
-tx, err := gen.dbConn.BeginTx(context.Background(), nil)
+tx, err := db.Begin()
 if err != nil {
     return err
 }
@@ -209,9 +207,7 @@ ttl := token.TTL              // "session" or "exp"
 ### Revoking a Token
 
 ```go
-import "context"
-
-tx, _ := gen.dbConn.BeginTx(context.Background(), nil)
+tx, _ := db.Begin()
 defer tx.Rollback()
 
 // Validate token first
@@ -247,7 +243,7 @@ Tokens can be marked as "fresh" for sensitive operations:
 accessToken, _, _ := gen.NewAccess(userID, true, false) // fresh=true
 
 // Check freshness
-tx, _ := gen.dbConn.BeginTx(context.Background(), nil)
+tx, _ := db.Begin()
 defer tx.Rollback()
 
 token, _ := gen.ValidateAccess(tx, accessToken)
@@ -364,8 +360,8 @@ CREATE INDEX IF NOT EXISTS idx_jwtblacklist_sub ON jwtblacklist(sub);
 
 ```go
 import (
-    "context"
     "gorm.io/gorm"
+    "gorm.io/driver/postgres"
 )
 
 // Get underlying *sql.DB from GORM
@@ -374,12 +370,21 @@ sqlDB, _ := gormDB.DB()
 
 // Create generator with sql.DB
 gen, _ := jwt.CreateGenerator(jwt.GeneratorConfig{
-    // ... config
-    DBConn: jwt.NewDBConnection(sqlDB),
+    AccessExpireAfter:  15,
+    RefreshExpireAfter: 1440,
+    FreshExpireAfter:   5,
+    TrustedHost:        "example.com",
+    SecretKey:          "your-secret-key",
+    DB:                 sqlDB,
+    DBType: jwt.DatabaseType{
+        Type:    jwt.DatabasePostgreSQL,
+        Version: "15",
+    },
+    TableConfig: jwt.DefaultTableConfig(),
 })
 
 // Use with transactions
-tx, _ := gen.dbConn.BeginTx(context.Background(), nil)
+tx, _ := sqlDB.Begin()
 defer tx.Rollback()
 
 token, _ := gen.ValidateAccess(tx, tokenString)
@@ -391,22 +396,35 @@ tx.Commit()
 
 ```go
 import (
-    "context"
+    "database/sql"
     "github.com/uptrace/bun"
+    "github.com/uptrace/bun/dialect/pgdialect"
+    "github.com/uptrace/bun/driver/pgdriver"
 )
 
-// Get underlying *sql.DB from Bun
-bunDB := bun.NewDB(sqldb, pgdialect.New())
-sqlDB := bunDB.DB // Already *sql.DB
+// Create *sql.DB connection first
+sqlDB := sql.Open(pgdriver.NewConnector(pgdriver.WithDSN(dsn)))
 
-// Create generator
+// Pass sql.DB to both Bun and JWT generator
+bunDB := bun.NewDB(sqlDB, pgdialect.New())
+
+// Create generator with the same sql.DB
 gen, _ := jwt.CreateGenerator(jwt.GeneratorConfig{
-    // ... config
-    DBConn: jwt.NewDBConnection(sqlDB),
+    AccessExpireAfter:  15,
+    RefreshExpireAfter: 1440,
+    FreshExpireAfter:   5,
+    TrustedHost:        "example.com",
+    SecretKey:          "your-secret-key",
+    DB:                 sqlDB,
+    DBType: jwt.DatabaseType{
+        Type:    jwt.DatabasePostgreSQL,
+        Version: "15",
+    },
+    TableConfig: jwt.DefaultTableConfig(),
 })
 
 // Use with transactions
-tx, _ := gen.dbConn.BeginTx(context.Background(), nil)
+tx, _ := sqlDB.Begin()
 defer tx.Rollback()
 
 token, _ := gen.ValidateAccess(tx, tokenString)
@@ -444,7 +462,7 @@ func main() {
         FreshExpireAfter:   5,
         TrustedHost:        "example.com",
         SecretKey:          "super-secret-key",
-        DBConn:             jwt.NewDBConnection(db),
+        DB:                 db,
         DBType: jwt.DatabaseType{
             Type:    jwt.DatabasePostgreSQL,
             Version: "15",
@@ -470,7 +488,7 @@ func main() {
     fmt.Printf("Refresh Token: %s (expires: %d)\n", refreshToken, refreshExp)
 
     // Validate access token
-    tx, _ := gen.dbConn.BeginTx(context.Background(), nil)
+    tx, _ := db.Begin()
     defer tx.Rollback()
     
     token, err := gen.ValidateAccess(tx, accessToken)
@@ -489,7 +507,7 @@ func main() {
     tx.Commit()
     
     // Try to validate revoked token
-    tx2, _ := gen.dbConn.BeginTx(context.Background(), nil)
+    tx2, _ := db.Begin()
     defer tx2.Rollback()
     
     _, err = gen.ValidateAccess(tx2, accessToken)