feat(stocks): add dividend growth analysis to stock analysis panel (#2927)

* feat(stocks): add dividend growth analysis to stock analysis panel

Shows yield, 5Y CAGR, frequency (quarterly/monthly/annual), payout
ratio, and ex-dividend date. Hidden for non-dividend stocks. Data
from Yahoo Finance dividend history.

* fix(stocks): bump cache key + fix partial-year CAGR + remove misleading avg yield

* fix(stocks): hydrate payout ratio, drop dead five-year yield, currency-aware dividend rate

- Add fetchPayoutRatio helper that calls Yahoo quoteSummary's summaryDetail
  module in parallel with the dividend chart fetch and returns the raw 0-1
  payout ratio (or undefined when missing/non-positive). The chart endpoint
  alone never returns payoutRatio, which is why it was hardcoded to 0.
- Make payout_ratio optional in proto and DividendProfile so a missing value
  is undefined instead of 0; remove five_year_avg_dividend_yield entirely
  (proto reserved 51) since it was always returned as 0 and never wired up.
- StockAnalysisPanel.renderDividendProfile now omits the Payout Ratio cell
  unless the value is present and > 0, formats it as (raw * 100).toFixed(1)%,
  and renders the dividend rate via Intl.NumberFormat with item.currency so
  EUR/GBP/JPY tickers no longer get a hardcoded "$" prefix.
- Bump live cache key v2 -> v3 so any cached snapshots persisted with the
  old shape are refetched once.
- Tests cover: payoutRatio populated from summaryDetail, payoutRatio
  undefined when summaryDetail returns 500 or raw=0, dividend response
  shape no longer contains fiveYearAvgDividendYield.

* fix(stocks): bump persisted history store to v3 to rotate pre-PR snapshots

Live analyze-stock cache was already bumped to v3, but the persisted
history store (premium-stock-store.ts) still used v2 keys for index/item
lookups. Pre-PR snapshots without the new dividend fields could pass the
age-only freshness check and suppress a live refetch, leaving the new
dividend section missing for up to 15 minutes.

Bumping the persisted store keys to v3 makes old snapshots invisible.
The data loader sees an empty history, triggers a live refetch, and
repopulates under the new v3 keys. Old v2 keys expire via TTL.

* fix(stocks): compute dividend CAGR correctly for quarterly/semiannual/annual payers

Previously computeDividendCagr() required at least 10 distinct dividend
months for a year to count as "full", which excluded every non-monthly
dividend payer (quarterly = 4 months, semiannual = 2, annual = 1).
CAGR therefore collapsed to 0/N/A for most ordinary dividend stocks.

The new check uses calendar position: any year strictly earlier than the
current calendar year is treated as complete, and the current in-progress
year is excluded to avoid penalizing stocks whose next payment has not
yet landed.

* test(stocks): pass analystData to buildAnalysisResponse after rebase onto #2926

docs/api/MarketService.openapi.yaml

@@ -1232,6 +1232,24 @@ components:
                     type: array
                     items:
                         $ref: '#/components/schemas/UpgradeDowngrade'
+                dividendYield:
+                    type: number
+                    format: double
+                trailingAnnualDividendRate:
+                    type: number
+                    format: double
+                exDividendDate:
+                    type: integer
+                    format: int64
+                    description: 'Warning: Values > 2^53 may lose precision in JavaScript'
+                payoutRatio:
+                    type: number
+                    format: double
+                dividendFrequency:
+                    type: string
+                dividendCagr:
+                    type: number
+                    format: double
         StockAnalysisHeadline:
             type: object
             properties: