Implement dashboard and audit log templates, add paginated audit log support

- Added `web/templates/{dashboard,audit,base,accounts,account_detail}.html` for a consistent UI.
- Implemented new audit log endpoint (`GET /v1/audit`) with filtering and pagination via `ListAuditEventsPaged`.
- Extended `AuditQueryParams`, added `AuditEventView` for joined actor/target usernames.
- Updated configuration (`goimports` preference), linting rules, and E2E tests.
- No logic changes to existing APIs.

internal/config/config.go

@@ -15,10 +15,10 @@ import (
 // Config is the top-level configuration structure parsed from the TOML file.
 type Config struct {
 	Server    ServerConfig    `toml:"server"`
+	MasterKey MasterKeyConfig `toml:"master_key"`
 	Database  DatabaseConfig  `toml:"database"`
 	Tokens    TokensConfig    `toml:"tokens"`
 	Argon2    Argon2Config    `toml:"argon2"`
-	MasterKey MasterKeyConfig `toml:"master_key"`
 }
 
 // ServerConfig holds HTTP listener and TLS settings.