[ci skip] Flatten module wrappers into stack roots

Remove the module "xxx" { source = "./module" } indirection layer
from all 66 service stacks. Resources are now defined directly in
each stack's main.tf instead of through a wrapper module.

- Merge module/main.tf contents into stack main.tf
- Apply variable replacements (var.tier -> local.tiers.X, renamed vars)
- Fix shared module paths (one fewer ../ at each level)
- Move extra files/dirs (factory/, chart_values, subdirs) to stack root
- Update state files to strip module.<name>. prefix
- Update CLAUDE.md to reflect flat structure

Verified: terragrunt plan shows 0 add, 0 destroy across all stacks.

stacks/f1-stream/module/files/internal/store/users.go

@@ -1,91 +0,0 @@
-package store
-
-import (
-	"fmt"
-
-	"f1-stream/internal/models"
-
-	"github.com/go-webauthn/webauthn/webauthn"
-)
-
-func (s *Store) LoadUsers() ([]models.User, error) {
-	s.usersMu.RLock()
-	defer s.usersMu.RUnlock()
-	var users []models.User
-	if err := readJSON(s.filePath("users.json"), &users); err != nil {
-		return nil, err
-	}
-	return users, nil
-}
-
-func (s *Store) GetUserByName(username string) (*models.User, error) {
-	s.usersMu.RLock()
-	defer s.usersMu.RUnlock()
-	var users []models.User
-	if err := readJSON(s.filePath("users.json"), &users); err != nil {
-		return nil, err
-	}
-	for _, u := range users {
-		if u.Username == username {
-			return &u, nil
-		}
-	}
-	return nil, nil
-}
-
-func (s *Store) GetUserByID(id string) (*models.User, error) {
-	s.usersMu.RLock()
-	defer s.usersMu.RUnlock()
-	var users []models.User
-	if err := readJSON(s.filePath("users.json"), &users); err != nil {
-		return nil, err
-	}
-	for _, u := range users {
-		if u.ID == id {
-			return &u, nil
-		}
-	}
-	return nil, nil
-}
-
-func (s *Store) CreateUser(user models.User) error {
-	s.usersMu.Lock()
-	defer s.usersMu.Unlock()
-	var users []models.User
-	if err := readJSON(s.filePath("users.json"), &users); err != nil {
-		return err
-	}
-	for _, u := range users {
-		if u.Username == user.Username {
-			return fmt.Errorf("username already exists")
-		}
-	}
-	users = append(users, user)
-	return writeJSON(s.filePath("users.json"), users)
-}
-
-func (s *Store) UpdateUserCredentials(userID string, creds []webauthn.Credential) error {
-	s.usersMu.Lock()
-	defer s.usersMu.Unlock()
-	var users []models.User
-	if err := readJSON(s.filePath("users.json"), &users); err != nil {
-		return err
-	}
-	for i, u := range users {
-		if u.ID == userID {
-			users[i].Credentials = creds
-			return writeJSON(s.filePath("users.json"), users)
-		}
-	}
-	return fmt.Errorf("user not found")
-}
-
-func (s *Store) UserCount() (int, error) {
-	s.usersMu.RLock()
-	defer s.usersMu.RUnlock()
-	var users []models.User
-	if err := readJSON(s.filePath("users.json"), &users); err != nil {
-		return 0, err
-	}
-	return len(users), nil
-}