Platform Architect Secure Modernization Environment for Legacy Software Takeovers

My company Oteia Systems takes over and modernizes existing business software — systems whose original builders are gone, documentation is thin, and the business still depends on them daily. We modernize them module by module, using AI coding tools heavily but under strict controls. I'm hiring the person who will design and build the platform this work runs on. This is an architecture-and-build role, not advisory: you will design it AND stand it up. What you will build (end to end): Secure discovery workflow — how we safely take over an inherited repository and environment: read-only first, evidence over documentation, risk mapping before any change. AI coding guardrails — sandboxed environments for Claude Code / Cursor and similar tools so client code and data never leak into models beyond what is needed; review gates, static analysis, and test-coverage requirements for AI-generated code. CI/CD pipelines — from commit to production release with human approval gates, small reviewable changes, rollback paths. Environment & data isolation — developers outside the EU must be able to work on live systems' modules while only ever seeing masked or synthetic test data, never production data. Environment separation, access control, secrets management, audit logging. Testing framework — characterization tests on inherited behavior, unit tests, integration tests, and controlled live verification, so modules can be modernized without breaking the business underneath. How we work: part-time to start (roughly 10–20 hrs/week), growing with our client pipeline. Long-term recurring work — this platform will carry every takeover we do. You'll work directly with me (founder) and with the senior engineers we're hiring in parallel. Requirements: You have personally designed and built (not just operated) developer platforms with strong isolation boundaries — regulated industries (banking, healthcare, government) are a strong plus. Hands-on with CI/CD (GitHub Actions / Azure DevOps / GitLab), IaC (Terraform / Bicep), secrets management, RBAC. Practical experience with AI coding tools and concrete opinions on how to control them. Comfortable inheriting legacy systems (.NET/C# common in our portfolio) — you don't need to be the modernizer, but you must understand what modernizers need. Individual freelancers only — no agencies, no subcontracting. Every hour billed must be personally yours. In your proposal, name one system where YOU designed the isolation boundary (who could see what, and how it was enforced). Generic proposals and tool lists will be declined.