feat: Add position scaling controls to settings UI

**UI Updates (settings page):**
Added new '📈 Position Scaling' section with:
- Enable/disable toggle (defaults to OFF)
- Min quality score slider (60-90, default 75)
- Min profit to scale (0-2%, default 0.4%)
- Scale size percent (10-100%, default 50%)
- Max position multiplier (1-3x, default 2.0x)
- Min ADX increase (0-15, default 5)
- Max price position for scale (50-90%, default 70%)

**Visual Feedback:**
- Purple-themed section with warning banner
- Real-time risk calculator showing:
  * Original position size (SOL example)
  * Scale addition amount
  * Total after 1 scale
  * Maximum possible position size
- Dynamic descriptions explain each parameter
- Warning: 'DISABLED by default' with red indicator

**API Updates:**
Extended /api/settings GET/POST to handle 7 new fields:
- ENABLE_POSITION_SCALING
- MIN_SCALE_QUALITY_SCORE
- MIN_PROFIT_FOR_SCALE
- MAX_SCALE_MULTIPLIER
- SCALE_SIZE_PERCENT
- MIN_ADX_INCREASE
- MAX_PRICE_POSITION_FOR_SCALE

**User Flow:**
1. Navigate to http://localhost:3001/settings
2. Scroll to '📈 Position Scaling' section
3. Toggle 'Enable Position Scaling' to 1
4. Adjust thresholds (defaults are conservative)
5. See live calculation of scaling impact
6. Click 'Save Settings'
7. Click 'Restart Bot' to apply

**Safety:**
- Feature OFF by default (requires explicit opt-in)
- Warning banner explains scaling behavior
- Risk calculator shows maximum exposure
- Conservative defaults prevent aggressive scaling
- All parameters adjustable via sliders

**Example:**
With defaults (SOL $210×10x = $2100):
- Scale adds: $1050 (50% of $2100)
- Total after 1 scale: $3150
- Max position (2x): $4200

User can now enable and configure position scaling without touching .env file!

app/api/settings/route.ts

@@ -87,6 +87,17 @@ export async function GET() {
       USE_TRAILING_STOP: env.USE_TRAILING_STOP === 'true' || env.USE_TRAILING_STOP === undefined,
       TRAILING_STOP_PERCENT: parseFloat(env.TRAILING_STOP_PERCENT || '0.3'),
       TRAILING_STOP_ACTIVATION: parseFloat(env.TRAILING_STOP_ACTIVATION || '0.5'),
+      
+      // Position Scaling
+      ENABLE_POSITION_SCALING: env.ENABLE_POSITION_SCALING === 'true',
+      MIN_SCALE_QUALITY_SCORE: parseInt(env.MIN_SCALE_QUALITY_SCORE || '75'),
+      MIN_PROFIT_FOR_SCALE: parseFloat(env.MIN_PROFIT_FOR_SCALE || '0.4'),
+      MAX_SCALE_MULTIPLIER: parseFloat(env.MAX_SCALE_MULTIPLIER || '2.0'),
+      SCALE_SIZE_PERCENT: parseFloat(env.SCALE_SIZE_PERCENT || '50'),
+      MIN_ADX_INCREASE: parseFloat(env.MIN_ADX_INCREASE || '5'),
+      MAX_PRICE_POSITION_FOR_SCALE: parseFloat(env.MAX_PRICE_POSITION_FOR_SCALE || '70'),
+      
+      // Safety
       MAX_DAILY_DRAWDOWN: parseFloat(env.MAX_DAILY_DRAWDOWN || '-50'),
       MAX_TRADES_PER_HOUR: parseInt(env.MAX_TRADES_PER_HOUR || '6'),
       MIN_TIME_BETWEEN_TRADES: parseInt(env.MIN_TIME_BETWEEN_TRADES || '600'),
@@ -112,6 +123,16 @@ export async function POST(request: NextRequest) {
     const updates = {
       MAX_POSITION_SIZE_USD: settings.MAX_POSITION_SIZE_USD.toString(),
       LEVERAGE: settings.LEVERAGE.toString(),
+      
+      // Per-symbol settings
+      SOLANA_ENABLED: settings.SOLANA_ENABLED.toString(),
+      SOLANA_POSITION_SIZE: settings.SOLANA_POSITION_SIZE.toString(),
+      SOLANA_LEVERAGE: settings.SOLANA_LEVERAGE.toString(),
+      ETHEREUM_ENABLED: settings.ETHEREUM_ENABLED.toString(),
+      ETHEREUM_POSITION_SIZE: settings.ETHEREUM_POSITION_SIZE.toString(),
+      ETHEREUM_LEVERAGE: settings.ETHEREUM_LEVERAGE.toString(),
+      
+      // Risk management
       STOP_LOSS_PERCENT: settings.STOP_LOSS_PERCENT.toString(),
       TAKE_PROFIT_1_PERCENT: settings.TAKE_PROFIT_1_PERCENT.toString(),
       TAKE_PROFIT_1_SIZE_PERCENT: settings.TAKE_PROFIT_1_SIZE_PERCENT.toString(),
@@ -124,6 +145,17 @@ export async function POST(request: NextRequest) {
       USE_TRAILING_STOP: settings.USE_TRAILING_STOP.toString(),
       TRAILING_STOP_PERCENT: settings.TRAILING_STOP_PERCENT.toString(),
       TRAILING_STOP_ACTIVATION: settings.TRAILING_STOP_ACTIVATION.toString(),
+      
+      // Position Scaling
+      ENABLE_POSITION_SCALING: settings.ENABLE_POSITION_SCALING.toString(),
+      MIN_SCALE_QUALITY_SCORE: settings.MIN_SCALE_QUALITY_SCORE.toString(),
+      MIN_PROFIT_FOR_SCALE: settings.MIN_PROFIT_FOR_SCALE.toString(),
+      MAX_SCALE_MULTIPLIER: settings.MAX_SCALE_MULTIPLIER.toString(),
+      SCALE_SIZE_PERCENT: settings.SCALE_SIZE_PERCENT.toString(),
+      MIN_ADX_INCREASE: settings.MIN_ADX_INCREASE.toString(),
+      MAX_PRICE_POSITION_FOR_SCALE: settings.MAX_PRICE_POSITION_FOR_SCALE.toString(),
+      
+      // Safety
       MAX_DAILY_DRAWDOWN: settings.MAX_DAILY_DRAWDOWN.toString(),
       MAX_TRADES_PER_HOUR: settings.MAX_TRADES_PER_HOUR.toString(),
       MIN_TIME_BETWEEN_TRADES: settings.MIN_TIME_BETWEEN_TRADES.toString(),