v0.0.31 — Regional Residency Routing

What's Changed

• fix(www): blog header headline "Writing" → "Field notes" by @msywulak in #3980
• docs: move www off the release pipeline (main-direct-to-prod like docs) by @msywulak in #3981
• refactor(api): "the process is the region" — delete per-request region routing by @msywulak in #3982
• feat(web): browser region-awareness — pre-auth regional API base + atlas_region persistence by @msywulak in #3983
• feat(api,web): host-only per-region session cookies + cross-origin CORS foundation (#3970) by @msywulak in #3985
• feat(web,api): signup reorder — region before the first identity write (#3972) by @msywulak in #4004
• feat(web,api): returning-user login front-door — stateless fan-out region router by @msywulak in #4005
• feat(www): SaaS-first homepage copy + CTAs, self-host as the second path by @msywulak in #4006
• test(api): /verify-prod-signup residency regression gate + verify-account teardown (#3974) by @msywulak in #4008

Full Changelog: v0.0.30...v0.0.31