dashboard: move live indicator to TOC sidebar on all pages; add live-data docs

- All four pages (index, workstreams, decisions, progress) now inject the
  live indicator into #observablehq-toc via injectTocTop("live-indicator", el)
  Left-aligned (no text-align: right), position:relative + padding-right for
  the ? button affordance

- decisions.md: splits the former combined "decisions-sidebar" widget into two
  separate injectTocTop calls — KPI box first (ends lower), live indicator
  second (ends at top); both now have their own stable ids

- withDocHelp(_liveEl, "/docs/live-data") wires the ? button on every page

- src/docs/live-data.md: new documentation page explaining poll interval (15s),
  indicator colour semantics, offline recovery, and which endpoints each page hits

- Removes the .live-bar CSS class from all pages; replaces with .live-indicator

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

dashboard/src/docs/live-data.md

@@ -0,0 +1,62 @@
+---
+title: Live Data — Reference
+---
+
+# Live Data — How the Dashboard Refreshes
+
+All dashboard pages poll the State Hub API automatically. No manual refresh is ever needed.
+
+---
+
+## Poll interval
+
+Every page fetches fresh data from `http://127.0.0.1:8000` every **15 seconds** using an async generator loop. The previous data stays visible while the next request is in flight, so the UI never goes blank.
+
+---
+
+## The live indicator
+
+The **●** dot in the top-right corner of each page shows the current connection state:
+
+| Indicator | Meaning |
+|---|---|
+| **● Live · updated HH:MM:SS** | Last poll succeeded — data is current as of that time |
+| **● Offline — run: `make api`** | API is unreachable — the dot turns red |
+
+The timestamp updates on every successful poll. If you see a time that is more than ~30 seconds in the past, the poll is stalled (browser tab backgrounded or network issue) — reloading the page resets the loop.
+
+---
+
+## Offline recovery
+
+If the API goes offline while you are viewing a page:
+
+1. The indicator turns red immediately on the next failed poll (within 15 s)
+2. The last successfully loaded data stays visible
+3. Once the API restarts, the indicator turns green on the next poll — **no page reload needed**
+
+To restart the API:
+
+```bash
+cd ~/the-custodian/state-hub
+make api          # starts uvicorn on 127.0.0.1:8000
+# or, if postgres is not running:
+make start        # db + migrate + api
+```
+
+---
+
+## Which data each page polls
+
+| Page | Endpoints |
+|---|---|
+| Overview | `/state/summary` |
+| Workstreams | `/workstreams/`, `/topics/`, `/state/summary` |
+| Decisions | `/decisions/?limit=500`, `/topics/` |
+| Progress | `/progress/?limit=500` |
+
+All endpoints are read-only GET requests. The dashboard never writes to the API.
+
+---
+
+*Poll interval: 15 s. Data is refreshed in the background — the page never reloads itself.*