feat: Add foundational documentation for security, workflow, and project management

- Create SECURITY.md to outline security policies and practices.
- Establish WORKFLOW.md detailing the project lifecycle from planning to retrospective.
- Introduce decision log structure in decisions/README.md for tracking architecture decisions.
- Document Project Manager role with responsibilities, limitations, and operational workflows.
- Implement templates for ADRs, bugs, meetings, projects, retrospectives, RFCs, roadmaps, and sprints.
- Set up memory logs for architecture and company-wide lessons learned.
- Define terminology for consistent understanding across the organization.

memory/lessons-learned.md

@@ -0,0 +1,20 @@
+# Lessons Learned
+
+Retrospective output, incident postmortems, and anything that answers "what would we do
+differently." See [../MEMORY.md](../MEMORY.md) and [../WORKFLOW.md](../WORKFLOW.md) — a
+retrospective that produces no entry here didn't do its job.
+
+## Log
+
+*No entries yet — no sprints have run.*
+
+Format for new entries:
+
+```
+### YYYY-MM-DD — <short title> (Sprint N, <project>, if applicable)
+
+<what happened>
+
+**Why:** <root cause, not just the symptom>
+**How to apply:** <the concrete change this produced — linked to the retro action item if any>
+```