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/healthcheck/healthcheck.go

@@ -13,8 +13,8 @@ import (
 	"go.uber.org/fx"
 )
 
-// HealthcheckParams defines the dependencies for creating a Healthcheck.
-type HealthcheckParams struct {
+// Params defines the dependencies for creating a Healthcheck.
+type Params struct {
 	fx.In
 
 	Globals  *globals.Globals
@@ -29,11 +29,11 @@ type Healthcheck struct {
 	StartupTime time.Time
 
 	log    *slog.Logger
-	params *HealthcheckParams
+	params *Params
 }
 
 // New creates a new Healthcheck instance.
-func New(lc fx.Lifecycle, params HealthcheckParams) (*Healthcheck, error) {
+func New(lc fx.Lifecycle, params Params) (*Healthcheck, error) {
 	s := new(Healthcheck)
 	s.params = &params
 	s.log = params.Logger.Get()
@@ -52,8 +52,8 @@ func New(lc fx.Lifecycle, params HealthcheckParams) (*Healthcheck, error) {
 	return s, nil
 }
 
-// HealthcheckResponse is the JSON response returned by the health endpoint.
-type HealthcheckResponse struct {
+// Response is the JSON response returned by the health endpoint.
+type Response struct {
 	Status        string `json:"status"`
 	Now           string `json:"now"`
 	UptimeSeconds int64  `json:"uptimeSeconds"`
@@ -64,8 +64,8 @@ type HealthcheckResponse struct {
 }
 
 // Healthcheck returns the current health status of the server.
-func (s *Healthcheck) Healthcheck() *HealthcheckResponse {
-	resp := &HealthcheckResponse{
+func (s *Healthcheck) Healthcheck() *Response {
+	resp := &Response{
 		Status:        "ok",
 		Now:           time.Now().UTC().Format(time.RFC3339Nano),
 		UptimeSeconds: int64(s.uptime().Seconds()),