feat(capability-registry): CUST-WP-0031 domain capability registry

- Migration p3k4l5m6n7o8: nullable repo_id FK on capability_catalog
- PATCH /capability-catalog/{id} endpoint for back-filling repo attribution
- register_capability MCP tool accepts optional repo_slug
- get_domain_summary now includes compact capabilities list (type+title+repo_slug)
- New get_capability_profile MCP tool: domain → repos → capabilities tree
- 6 repo descriptions populated; 25 catalog entries attributed to repos
- 9 new capabilities registered for personhood, foerster_capabilities, coulomb_social
- TOOLS.md: Capability Catalog & Requests section with full tool reference

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

migrations/versions/p3k4l5m6n7o8_add_repo_id_to_capability_catalog.py

@@ -0,0 +1,28 @@
+"""add repo_id to capability_catalog
+
+Revision ID: p3k4l5m6n7o8
+Revises: o2j3k4l5m6n7
+Create Date: 2026-03-31
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import UUID
+
+revision = "p3k4l5m6n7o8"
+down_revision = "o2j3k4l5m6n7"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "capability_catalog",
+        sa.Column("repo_id", UUID(as_uuid=True), sa.ForeignKey("managed_repos.id", ondelete="SET NULL"), nullable=True),
+    )
+    op.create_index("ix_capability_catalog_repo_id", "capability_catalog", ["repo_id"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_capability_catalog_repo_id", table_name="capability_catalog")
+    op.drop_column("capability_catalog", "repo_id")