add Eurostat + UK ONS sources; valuation/bubble/economy/bonds groups; aggregate read; market-open header

Three new data sources hooked into the existing SOURCES registry. All
open APIs, no keys:

  - EUROSTAT: prefix EUROSTAT:dataset?dim=val&... — current EU bond
    yields (Bund/OAT/BTP/EZ) and Eurozone economic indicators that
    FRED's OECD-mirror series stopped updating in 2022-2023.
  - ONS: prefix ONS:topic/cdid/dataset — current UK CPI, unemployment,
    GDP, industrial production. Replaces the 5+ month-stale FRED
    LRHUTTTTGBM156S mirror.

New indicator groups in default.toml feed the strategic/fundamental
lens we converged on: valuation (CAPE/Buffett anchors), bubble_watch
(SKEW/VVIX/RSP vs SPY/HYG vs TLT/IPO/crypto), economy (multi-region,
ALL current-or-stale-flagged), bonds (UK/EU/US/JPN sovereign yields).

Indicator panel now opens with an AI "read" interpretation per group
(generated hourly at :07 UTC alongside an aggregate cross-group read
shown in the dashboard header). The aggregate is grounded by a markets
strip — NYSE/LSE/Frankfurt/Tokyo/HK/Shanghai with open/closed LEDs and
next-open countdown, computed locally from each exchange's tz.

Other UX bits: indicator-row tooltips populated from TOML notes;
rows whose last observation is >90 days old get a 'stale' chip;
ghost symbols (in DB but no longer in TOML) filtered out of the
panel; Eurostat/ONS symbols display as short codes rather than the
full API path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/jobs/market_job.py

@@ -51,7 +51,9 @@ async def run() -> None:
                 currency=q.currency,
                 as_of=q.as_of,
                 changes=q.changes or None,
-                error=q.error,
+                # Truncate to the column's 255-char limit. Some providers
+                # return verbose redirect chains that blow the limit.
+                error=(q.error[:250] if q.error else None),
                 fetched_at=now,
             ))
         await session.commit()