feat(todo-api): add full-stack POC demonstrating micro-lib v0.9.0

Runnable REST API exercising every micro-lib tier in a containerless setup: N-layer architecture, SQLite persistence, header-based auth simulating Firebase output, and bit-mask RBAC enforcement.

What's included:
- cmd/todo-api: minimal main delegating to application.Run
- internal/application: full object graph wiring — launcher, sqlite, httpserver, httpmw stack, routes in BeforeStart
- internal/domain: User entity, ResourceTodos constant, PermReadTodo/PermWriteTodo bit positions
- internal/repository: TodoRepository, UserRepository, DBPermissionProvider (SQLite via modernc)
- internal/service: TodoService, UserService with interface-based dependencies
- internal/handler: TodoHandler, UserHandler using httputil adapters and valid for input validation
- internal/middleware: Auth (X-User-ID → rbac.Identity) and Require (bit-mask permission gate)
- logAdapter: bridges logz.Logger.With return type to httpmw.Logger interface
- SQLite schema: users, user_role (bitmask), todos; migrations run in BeforeStart
- Routes: POST /users (open), GET+POST /todos (RBAC), GET /users (RBAC)

Tested-via: todo-api POC integration
Reviewed-against: docs/adr/

.gitignore

@@ -0,0 +1,41 @@
+# Binaries
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with go test -c
+*.test
+
+# Output of go build
+*.out
+
+# Dependency directory
+vendor/
+
+# Go workspace file
+go.work
+go.work.sum
+
+# Environment files
+.env
+.env.*
+
+# Editor / IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# Local DB
+*.db
+
+# OS
+.DS_Store
+Thumbs.db
+
+# VCS files
+COMMIT.md
+RELEASE.md