refactor: reorganize backend with Wire injection

[fuchencong]

Summary

• reorganize the backend into app, conf, server, service, biz, data, and worker layers
• assemble server, worker, and migrator processes with Wire provider sets
• adopt functional options for process and component configuration
• isolate PostgreSQL, Gin, Viper, Hatchet, and SCC dependencies at their adapter boundaries
• update sqlc generation, CI, release, Docker, Makefile, and architecture documentation
• add architecture, OpenAPI, CLI, workflow payload, and option contract tests to prevent regressions

Compatibility

Existing CLI commands, HTTP/OpenAPI routes, workflow names and payloads, configuration behavior, metrics, and data migrations are preserved. Database driver errors are translated at the data boundary so HTTP and worker retry semantics remain stable.

Validation

• make generate
• make test vet build
• go test -race ./...
• make integration-test against PostgreSQL 17
• make lint (0 issues)
• make frontend-i18n frontend-lint frontend-build
• production ldflags CLI build plus version and --help smoke tests
• go mod tidy
• git diff --check
• Wire generated-output diff and legacy import-path audit