feat(ep-td+dashboard): complete CUST-WP-0004 EP/TD tracking workstream

EP catalogue (all domains):
- EP-RAIL-001 ep_id patched (schema fix: add ep_id to EPUpdate)
- EP-RAIL-003 (git bare-repo mirrors) and EP-RAIL-004 (offsite secondary
  backup) registered from railiance-cluster/docs/backup-restore.md
- EP-CUST-003..007 ep_ids assigned to existing custodian EPs
- EP-CUST-008 (State Hub API auth) and EP-CUST-009 (update_workstream MCP
  tool) registered as new custodian extension points

TD catalogue (railiance — first 5 items):
- TD-RAIL-001: backup cron runs as root without audit trail (high/security)
- TD-RAIL-002: k3s kubeconfig world-readable mode 644 (medium/security)
- TD-RAIL-003: no Ansible role unit tests (medium/test)
- TD-RAIL-004: age key extracted via awk — fragile (medium/impl)
- TD-RAIL-005: etcd snapshot retention uncoordinated (low/impl)

Dashboard (T08 + T10):
- Extract API URL and POLL to src/components/config.js; all 15 pages
  now import from the shared module (contributions/goals keep custom POLL)
- Shared .kpi-infobox, .filter-bar, .filter-search/.filter-owner CSS
  moved to observablehq.config.js head <style> block; removed from 9 pages
- Build: 0 errors, 0 warnings

API (T09):
- progress.py: limit param now Query(100, le=1000) — prevents unbounded
  list requests; closes TD-CUST-004 for the only endpoint that had limit

CUST-WP-0004 marked completed (all 10 tasks done).

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

dashboard/observablehq.config.js

@@ -69,6 +69,13 @@ export default {
     },
   ],
   theme: ["air", "near-midnight"],
-  head: `<link rel="icon" href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>🗄️</text></svg>">`,
+  head: `<link rel="icon" href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>🗄️</text></svg>">
+<style>
+.kpi-infobox { background: var(--theme-background-alt, #f9f9f9); border: 1px solid var(--theme-foreground-faint, #e0e0e0); border-radius: 10px; padding: 0.75rem 1rem; position: relative; box-shadow: 0 1px 6px rgba(0,0,0,0.07); margin-bottom: 1.25rem; }
+.kpi-infobox-title { font-size: 0.68rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--theme-foreground-muted, #888); margin-bottom: 0.55rem; padding-right: 1.6rem; }
+.filter-bar { display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center; margin-bottom: 1rem; }
+.filter-search, .filter-owner { display: flex; align-items: center; }
+.filter-search input, .filter-owner input { height: 30px; font-size: 0.85rem; padding: 0.25rem 0.5rem; border-radius: 6px; border: 1px solid var(--theme-foreground-faint, #ccc); background: var(--theme-background, #fff); font-family: inherit; color: inherit; }
+</style>`,
   footer: "Custodian State Hub — local-first, append-only, sovereignty-preserving.",
 };