release: 1.0.0, a changelog, one .env.example and the docs to match

- CHANGELOG.md and CHANGELOG.pt-BR.md, from the project history.
- .env.example now serves development and production; scripts/init-env.sh
  (make env) creates .env with random secrets. .env.production.example is gone.
- docs/RELEASING.md: the pipeline, how a version is cut and deployed, the runners.
- DEPLOYMENT.md and both READMEs updated for Gitea and the new env flow.
- Service versions set to 1.0.0.
- CI: the proxy network step is idempotent and the stack is torn down always,
  since the runner's Docker daemon now outlives a job.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Makefile

@@ -1,4 +1,8 @@
-.PHONY: up down logs test test-db-up test-db-down lint migrate-up migrate-down gen-dev-cert seed preflight create-admin reset-password reset-mfa
+.PHONY: env up down logs test test-db-up test-db-down lint migrate-up migrate-down gen-dev-cert seed preflight create-admin reset-password reset-mfa
+
+# .env from .env.example with fresh secrets; refuses to overwrite an existing one.
+env:
+	scripts/init-env.sh
 
 # Local development builds from source; production pulls what CI published.
 up: