feat(gold): Gold Intelligence v2 — positioning depth, returns, drivers (#3034)

* feat(gold): richer Gold Intelligence panel with positioning, returns, drivers

* fix(gold): restore leveragedFunds fields and derive P/S netPct in legacy fallback

Review catch on PR #3034:

1. seed-cot.mjs stopped emitting leveragedFundsLong/Short during the v2
   refactor, which would zero out the Leveraged Funds bars in the existing
   CotPositioningPanel on the next seed run. Re-read lev_money_* from the
   TFF rows and keep the fields on the output (commodity rows don't have
   this breakdown, stay at 0).
2. get-gold-intelligence legacy fallback hardcoded producerSwap.netPct to 0,
   meaning a pre-v2 COT snapshot rendered a neutral 0% Producer/Swap bar
   on deploy until seed-cot reran. Derive netPct from dealerLong/dealerShort
   (same formula as the v2 seeder). OI share stays 0 because open_interest
   wasn't captured pre-migration; clearly documented now.

Tests: added two regression guards (leveragedFunds preserved for TFF,
commodity rows emit 0 for those fields).

* fix(gold): make enrichment layer monitored and honest about freshness

Review catch on PR #3034:

- seed-commodity-quotes now writes seed-meta:market:gold-extended via
  writeExtraKeyWithMeta on every successful run. Partial / failed fetches
  skip BOTH the data write and the meta bump, so health correctly reports
  STALE_SEED instead of masking a broken Yahoo fetch with a green check.
- Require both gold (core) AND at least one driver/silver before writing,
  so a half-successful run doesn't overwrite healthy prior data with a
  degraded payload.
- Handler no longer stamps updatedAt with new Date() when the enrichment
  key is missing. Emits empty string so the panel's freshness indicator
  shows "Updated —" with a dim dot, matching reality — enrichment is
  missing, not fresh.
- Health: goldExtended entry in STANDALONE_KEYS + SEED_META (maxStaleMin
  30, matching commodity quotes), and seed-health.js advertises the
  domain so upstream monitors pick it up.

The panel already gates session/returns/drivers sections on presence, so
legacy panels without the enrichment layer stay fully functional.

docs/api/MarketService.openapi.yaml

@@ -1939,6 +1939,16 @@ components:
                     type: string
                 unavailable:
                     type: boolean
+                session:
+                    $ref: '#/components/schemas/GoldSessionRange'
+                returns:
+                    $ref: '#/components/schemas/GoldReturns'
+                range52w:
+                    $ref: '#/components/schemas/GoldRange52w'
+                drivers:
+                    type: array
+                    items:
+                        $ref: '#/components/schemas/GoldDriver'
         GoldCrossCurrencyPrice:
             type: object
             properties:
@@ -1954,18 +1964,85 @@ components:
             properties:
                 reportDate:
                     type: string
-                managedMoneyLong:
-                    type: number
-                    format: double
-                managedMoneyShort:
-                    type: number
-                    format: double
+                nextReleaseDate:
+                    type: string
+                openInterest:
+                    type: string
+                    format: int64
+                managedMoney:
+                    $ref: '#/components/schemas/GoldCotCategory'
+                producerSwap:
+                    $ref: '#/components/schemas/GoldCotCategory'
+        GoldCotCategory:
+            type: object
+            properties:
+                longPositions:
+                    type: string
+                    format: int64
+                shortPositions:
+                    type: string
+                    format: int64
                 netPct:
                     type: number
                     format: double
-                dealerLong:
+                oiSharePct:
                     type: number
                     format: double
-                dealerShort:
+                wowNetDelta:
+                    type: string
+                    format: int64
+        GoldSessionRange:
+            type: object
+            properties:
+                dayHigh:
+                    type: number
+                    format: double
+                dayLow:
+                    type: number
+                    format: double
+                prevClose:
+                    type: number
+                    format: double
+        GoldReturns:
+            type: object
+            properties:
+                w1:
+                    type: number
+                    format: double
+                m1:
+                    type: number
+                    format: double
+                ytd:
+                    type: number
+                    format: double
+                y1:
+                    type: number
+                    format: double
+        GoldRange52w:
+            type: object
+            properties:
+                hi:
+                    type: number
+                    format: double
+                lo:
+                    type: number
+                    format: double
+                positionPct:
+                    type: number
+                    format: double
+        GoldDriver:
+            type: object
+            properties:
+                symbol:
+                    type: string
+                label:
+                    type: string
+                value:
+                    type: number
+                    format: double
+                changePct:
+                    type: number
+                    format: double
+                correlation30d:
                     type: number
                     format: double