chore(consolidation): migrate from blackroad-os-ideas and blackroad-os-research

## Summary
- Migrates roadmaps and RFCs from `blackroad-os-ideas`
- Migrates research papers from `blackroad-os-research`
- Part of Phase 1 BlackRoad OS consolidation

## Files Added
- `docs/roadmap/` - 2025 roadmaps
- `docs/rfc/` - RFC templates
- `docs/ideas/` - Idea proposals
- `docs/papers/` - Research papers (PS-SHA, SIG, finance automation)
- `docs/research/` - Research prompts

## Test plan
- [ ] Verify docs build
- [ ] After merge, archive source repos

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Alexa Louise <YOUR_REAL_EMAIL@EXAMPLE.COM>
Co-authored-by: Claude <noreply@anthropic.com>

docs/ideas/concepts/sig-agent-identity-card.md

@@ -0,0 +1,23 @@
+# Concept Card: SIG Factor Tree Identity Assignment
+
+## 1. Objective
+Enable consistent, cryptographically rooted identities for agents using SIG factor trees so actions are auditable across BlackRoad OS components.
+
+## 2. Mechanism
+- Generate agent identity seeds from SIG factor trees and store lineage metadata alongside operational credentials.
+- Expose a verification endpoint for other agents and services to confirm provenance before trusting actions or data.
+
+## 3. Dependencies
+- `blackroad-os-operator` for identity issuance workflows.
+- `blackroad-os-core` for shared cryptography helpers.
+- Registry updates for agent identity schemas.
+
+## 4. Risks / Unknowns
+- How to rotate SIG-derived keys without breaking lineage guarantees.
+- Interaction with compliance logging and PS-SHA∞ journaling.
+- Potential performance impact during high-frequency verifications.
+
+## 5. Next Steps
+- [ ] Validate via research on SIG rotation patterns.
+- [ ] Draft proposal detailing issuance and revocation flows.
+- [ ] Review with orchestrator and compliance stakeholders.