feat(capability-requests): add cross-domain capability catalog and request routing

Introduces a capability catalog (CUST-WP-0022) so domains can advertise what
they provide and agents can request capabilities from other domains with
auto-routing, lifecycle tracking, and task-unblocking on completion.

- New models: CapabilityCatalog, CapabilityRequest with full lifecycle
  (requested → accepted → in_progress → ready_for_review → completed/rejected/withdrawn)
- Migration i6d7e8f9a0b1: capability_catalog + capability_requests tables
- Router /capability-catalog and /capability-requests with accept/status endpoints
- 7 new MCP tools: register_capability, list_capabilities, request_capability,
  accept_capability_request, update_capability_request_status,
  list_capability_requests, get_capability_request
- StateSummary gains open_capability_requests count
- Dashboard: capability-requests.md page + docs/capabilities.md + docs/scope.md
- SCOPE.md: three seed capabilities documented (MCP registration, state tracking, SBOM)
- scope.template: Provided Capabilities section with example block
- scripts/ingest_capabilities.py + make ingest-capabilities[/-all] targets

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Makefile

@@ -169,6 +169,20 @@ ingest-sbom:
 		$(if $(REPO_PATH),--repo-path "$(REPO_PATH)") \
 		$(if $(DRY_RUN),--dry-run)
 
+## Ingest capability declarations from SCOPE.md into the catalog.
+## Usage: make ingest-capabilities REPO=the-custodian [REPO_PATH=/home/worsch/the-custodian]
+## Or:    make ingest-capabilities-all
+## Add DRY_RUN=1 to preview without writing.
+ingest-capabilities:
+	@test -n "$(REPO)" || (echo "ERROR: REPO is required."; exit 1)
+	uv run python scripts/ingest_capabilities.py --repo "$(REPO)" \
+		$(if $(REPO_PATH),--repo-path "$(REPO_PATH)") \
+		$(if $(DRY_RUN),--dry-run)
+
+ingest-capabilities-all:
+	uv run python scripts/ingest_capabilities.py --all \
+		$(if $(DRY_RUN),--dry-run)
+
 ## Run SBOM capture agent for a repo — generates/updates sbom-tools.yaml.
 ## Usage: make capture-tools REPO=railiance-infra [REPO_PATH=/home/worsch/railiance-infra]
 ## Add DRY_RUN=1 to preview without writing.