Add ML and QA Engineer documentation and workflows

- Introduced ML Engineer role with detailed responsibilities, success metrics, and workflow documentation.
- Established QA Engineer role with clear responsibilities, limitations, and success metrics.
- Created structured onboarding files for both roles, including README, ROLE, RESPONSIBILITIES, WORKFLOW, and SUCCESS_METRICS.
- Defined limitations for both roles to clarify boundaries and escalation paths.
- Enhanced security engineer documentation with responsibilities, limitations, and workflow for handling security reviews and findings.

employees/frontend/WORKFLOW.md

@@ -0,0 +1,56 @@
+# Workflow (Frontend Engineer operational loop)
+
+This is the Frontend Engineer's specific loop within the company-wide lifecycle defined in
+`../../WORKFLOW.md`. Read that document first — this one assumes it.
+
+## Claiming a Task
+
+```
+1. Pick from the active sprint's Todo column (assigned, or self-claimed and confirmed by the
+   Project Manager per ../../PLANE.md)
+2. Read the acceptance criteria fully, including the intended UX outcome — if the intended
+   look/behavior isn't clear, ask the Project Manager before starting
+3. Move the Task to In Progress
+```
+
+## Implementing
+
+```
+1. Branch per ../../GITEA.md naming: frontend<n>/<task-id>-<short-description>
+2. Implement against ../../CODING_STANDARDS.md, matching existing component/pattern conventions
+3. Actually run the interface and interact with it — don't rely on compiling/unit tests alone
+4. Write tests that verify real behavior; add a regression test for bug fixes
+5. Update any documentation this change makes stale, in the same PR where feasible
+```
+
+## Opening a PR
+
+```
+1. Commit per ../../GITEA.md message format, with the Task trailer
+2. Open PR linked to the Task; include enough detail (screenshot, interaction description) for
+   a reviewer to evaluate the actual user-facing result, not just the diff
+3. Move Task to In Review
+```
+
+## Responding to review
+
+```
+1. Architect or peer review comes back — engage with each comment, either with a change or
+   clearly reasoned pushback
+2. Re-request review after addressing feedback
+3. Once approved and CI (../../ACT_RUNNER.md) is green, the reviewer merges — not you
+```
+
+## After merge, awaiting QA
+
+```
+1. Task moves to QA per ../../WORKFLOW.md
+2. If QA passes (functionally and on usability): Task closes
+3. If QA rejects: Task returns to In Progress with QA's findings — fix the actual issue
+4. If you believe the rejection is mistaken: escalate to the Architect for adjudication
+   (../architect/WORKFLOW.md) rather than arguing directly with QA
+```
+
+## When something doesn't fit this loop
+
+Escalate the gap per `LIMITATIONS.md`. If it recurs, flag it as worth updating this document.