Fix all lint issues and update AGENTS.md workflow rules

- Fix stuttering type names (e.g. config.ConfigParams → config.Params)
- Add doc comments to all exported types/functions/methods
- Add package doc comments to all packages
- Fix JSON tags to camelCase
- Extract magic numbers to constants
- Add blank lines per nlreturn/wsl_v5 rules
- Use errors.Is() for error comparison
- Unexport NewLoggingResponseWriter (not used externally)
- Replace for-range on ctx.Done() with channel receive
- Rename unused parameters to _
- AGENTS.md: all changes via feature branches, no direct main commits

internal/db/db.go

@@ -29,10 +29,10 @@ const (
 // SchemaFiles contains embedded SQL migration files.
 //
 //go:embed schema/*.sql
-var SchemaFiles embed.FS //nolint:gochecknoglobals
+var SchemaFiles embed.FS
 
-// DatabaseParams defines the dependencies for creating a Database.
-type DatabaseParams struct {
+// Params defines the dependencies for creating a Database.
+type Params struct {
 	fx.In
 
 	Logger *logger.Logger
@@ -43,7 +43,7 @@ type DatabaseParams struct {
 type Database struct {
 	db     *sql.DB
 	log    *slog.Logger
-	params *DatabaseParams
+	params *Params
 }
 
 // GetDB returns the underlying sql.DB connection.
@@ -67,7 +67,7 @@ func (s *Database) NewChannel(id int64, name, topic, modes string, createdAt, up
 }
 
 // New creates a new Database instance and registers lifecycle hooks.
-func New(lc fx.Lifecycle, params DatabaseParams) (*Database, error) {
+func New(lc fx.Lifecycle, params Params) (*Database, error) {
 	s := new(Database)
 	s.params = &params
 	s.log = params.Logger.Get()
@@ -80,7 +80,7 @@ func New(lc fx.Lifecycle, params DatabaseParams) (*Database, error) {
 
 			return s.connect(ctx)
 		},
-		OnStop: func(ctx context.Context) error {
+		OnStop: func(_ context.Context) error {
 			s.log.Info("Database OnStop Hook")
 
 			if s.db != nil {