feat(state-hub): implement v0.5 — dynamic domains & multi-repo

Replaces the hardcoded 6-domain PostgreSQL ENUM with a first-class
`domains` DB table, and adds a `managed_repos` table for multi-repo
support per domain.

P1 — Domain as a DB entity:
- Migration b1c2d3e4f5a6: creates `domains` table, migrates topics.domain
  ENUM column to domain_id FK, drops the domain ENUM type
- Domain ORM model (api/models/domain.py) + Pydantic schemas
- Domain API router: GET/POST /domains/, GET/PATCH /domains/{slug}/,
  rename and archive endpoints with EP/TD cascade on rename
- Topic model updated: domain_id FK + @property domain_slug for
  backwards-compatible JSON serialization (field renamed domain → domain_slug)
- TopicCreate/TopicRead updated; seed.py rewritten to use FK lookup

P2 — Multi-repo support:
- ManagedRepo ORM model (api/models/managed_repo.py) + schemas
- Repo API router: GET/POST /repos/, GET/PATCH /repos/{slug}/, archive
- Makefile: add-domain, rename-domain, add-repo, list-repos targets
- register_project.sh: verify domain via /domains/ API + POST /repos/

P3 — MCP tools & live validation:
- 6 new MCP tools: list_domains, create_domain, rename_domain,
  archive_domain, list_domain_repos, register_repo
- EP/TD routers: replace hardcoded VALID_DOMAINS set with per-request
  DB lookup — returns 422 with list of valid slugs on unknown domain
- State summary: adds domains: list[DomainSummary] (slug, name,
  repo_count, active_workstream_count, ep_count, td_count)
- TOOLS.md updated with domain management section

P4 — Dashboard:
- New domains.md page with KPI row + domain cards + repo lists
- domains.json.py + repos.json.py data loaders
- Domains page added to observablehq.config.js nav
- workstreams.md, extensions.md, techdept.md: domain_slug fix +
  dynamic domain list loaded from /domains/ API (no longer hardcoded)

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

Makefile

@@ -1,4 +1,4 @@
-.PHONY: install install-cli db db-tools migrate seed api dashboard check start clean register-project validate-adr
+.PHONY: install install-cli db db-tools migrate seed api dashboard check start clean register-project validate-adr add-domain rename-domain add-repo list-repos
 
 COMPOSE = docker compose -f infra/docker-compose.yml --env-file .env
 
@@ -45,6 +45,34 @@ register-project:
 	@test -n "$(PROJECT_PATH)" || (echo "ERROR: PROJECT_PATH is required."; exit 1)
 	scripts/register_project.sh "$(DOMAIN)" "$(PROJECT_PATH)"
 
+## Add a second repo to an existing domain: make add-repo DOMAIN=railiance REPO_PATH=/home/worsch/railiance-infra
+add-repo:
+	@test -n "$(DOMAIN)" || (echo "ERROR: DOMAIN is required."; exit 1)
+	@test -n "$(REPO_PATH)" || (echo "ERROR: REPO_PATH is required."; exit 1)
+	scripts/register_project.sh "$(DOMAIN)" "$(REPO_PATH)" --additional
+
+## Create a new domain: make add-domain DOMAIN=my_domain NAME="My Domain"
+add-domain:
+	@test -n "$(DOMAIN)" || (echo "ERROR: DOMAIN is required (slug)."; exit 1)
+	@test -n "$(NAME)" || (echo "ERROR: NAME is required (display name)."; exit 1)
+	curl -sf -X POST http://127.0.0.1:8000/domains/ \
+	  -H "Content-Type: application/json" \
+	  -d "{\"slug\": \"$(DOMAIN)\", \"name\": \"$(NAME)\"}" | python3 -m json.tool
+
+## Rename a domain: make rename-domain DOMAIN=old_slug NEW_SLUG=new_slug NEW_NAME="New Name"
+rename-domain:
+	@test -n "$(DOMAIN)" || (echo "ERROR: DOMAIN (old slug) is required."; exit 1)
+	@test -n "$(NEW_SLUG)" || (echo "ERROR: NEW_SLUG is required."; exit 1)
+	@test -n "$(NEW_NAME)" || (echo "ERROR: NEW_NAME is required."; exit 1)
+	curl -sf -X PATCH http://127.0.0.1:8000/domains/$(DOMAIN)/rename \
+	  -H "Content-Type: application/json" \
+	  -d "{\"new_slug\": \"$(NEW_SLUG)\", \"new_name\": \"$(NEW_NAME)\"}" | python3 -m json.tool
+
+## List repos for a domain: make list-repos DOMAIN=railiance
+list-repos:
+	@test -n "$(DOMAIN)" || (echo "ERROR: DOMAIN is required."; exit 1)
+	curl -sf "http://127.0.0.1:8000/repos/?domain=$(DOMAIN)" | python3 -m json.tool
+
 ## Check a repo for ADR-001 compliance: make validate-adr REPO=/path/to/repo [DOMAIN=custodian]
 validate-adr:
 	@test -n "$(REPO)" || (echo "ERROR: REPO is required. Usage: make validate-adr REPO=<path> [DOMAIN=<slug>]"; exit 1)