feat(registry): initialize X-Frames Blueprint Registry with 4 demo blueprints

- Add security-assessment-v1, it-incident-triage-v1, common-grounds-deploy-v1, org-bootstrap-v1
- Add index.json registry index with full metadata
- Add BLUEPRINT_SCHEMA_v1_0.json validation schema
- Add SCHEMA.md reference docs

Co-Authored-By: Eyean (EOA0000) <eyean@eios.local>

SCHEMA.md

@@ -0,0 +1,15 @@
+# Blueprint Schema Reference
+
+All blueprints in this registry conform to [BLUEPRINT_SCHEMA_v1_0.json](BLUEPRINT_SCHEMA_v1_0.json).
+
+## Required Fields
+- `blueprint_id` — unique namespace/id string (e.g. `security/assessment-report-v1`)
+- `version` — semver string
+- `name` — human-readable name
+- `blueprint_type` — one of: `bridge_workflow`, `eios_tool`, `harness_config`, `deployment_template`
+- `author` — `entity_id`, `display_name`
+- `license` — `commercial`, `open_source`, `internal`
+- `description` — short description (≤200 chars)
+
+## Submission
+See [EIOS Blueprint Marketplace](https://ecp.xrayvu.com) for submission instructions.