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>

dashboard/src/workstreams.md

@@ -24,7 +24,7 @@ const wsState = (async function*() {
         const topicMap = Object.fromEntries(topicList.map(t => [t.id, t]));
         data = wsList.map(w => ({
           ...w,
-          domain: topicMap[w.topic_id]?.domain ?? "unknown",
+          domain: topicMap[w.topic_id]?.domain_slug ?? "unknown",
           topic_title: topicMap[w.topic_id]?.title ?? "—",
         }));
         // open_workstreams from summary carry depends_on / blocks lists
@@ -214,8 +214,11 @@ if (_h1) { _h1.style.position = "relative"; withDocHelp(_h1, "/docs/workstreams"
 ```js
 import {MultiSelect} from "./components/multiselect.js";
 
-// Static options — no dependency on `data`, so selections survive polls
-const DOMAINS  = ["custodian", "railiance", "markitect", "coulomb_social", "personhood", "foerster_capabilities"];
+// Load domain slugs from API (dynamic — works with new domains after v0.5)
+const _domainsResp = await fetch(`${API}/domains/?status=active`).catch(() => null);
+const DOMAINS = _domainsResp?.ok
+  ? (await _domainsResp.json()).map(d => d.slug)
+  : ["custodian", "railiance", "markitect", "coulomb_social", "personhood", "foerster_capabilities"];
 const STATUSES = ["active", "blocked", "completed", "archived"];
 
 // Create filter form without displaying — shown below the chart