feat(market): historical chart intervals, stats overlay, configurable outline, easier resize

Chart:
- The price chart now plots the historical CoinGecko series with a Live/1H/1D/1W/1M
  interval selector (top-left of the chart). Live = in-session buffer; 1H uses the
  intraday 5-min series, 1D/1W/1M the daily series (via pfSparklineSeries). X-axis
  labels are interval-aware ("~5h"/"~3d"/"~2w"/"~4mo"). Market-tab open kicks the
  self-throttled market_chart fetch so history populates promptly.
- 24H volume + market cap moved from their own row onto the chart's top strip
  (right side, next to the refresh button), reclaiming the empty band above the
  chart; the hero header now holds just the price row + separator.
- More bottom padding under the plot so the time labels and the DRGX/USDT pair
  buttons aren't crowded against the card edges.

Portfolio groups:
- Accent-outline opacity is now configurable per group (0-100%, default 25%) via a
  slider in the editor's Appearance column; applied to the card + preview outline.
- Resize grip enlarged (14->20px) and a live "W x H" size readout is drawn while
  resizing, so shrinking a group to the 4x3 minimum is reliable and visible.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/config/settings.h

@@ -80,6 +80,7 @@ public:
         std::vector<std::string> addresses;
         std::string icon;           // project_icons wallet-icon name; empty = no icon
         unsigned int color = 0;     // packed IM_COL32 accent; 0 = theme default
+        int outlineOpacity = 25;    // accent-outline opacity, percent (0-100)
         // Per-group price data. priceBasis: 0 = live market (USD), 1 = live market (BTC),
         // 2 = DRGX only (no fiat value), 3 = manual price. Defaults preserve prior behavior
         // (show DRGX + USD value).