Add Hyperliquid fee tier selector — 7 VIP levels × 7 staking tiers

config/fee_tiers.py: complete Hyperliquid fee schedule with perps and spot
base rates plus staking discount multipliers. effective_rate() computes
the actual fee after staking discount. get_perp_fees() returns the
effective rate for a given VIP tier, staking tier, and fee model.

Backtest runner: added --fee-tier (0-6) and --staking-tier flags.
Regenerated all 12 backtests at VIP 0 baseline. Runner now shows fee tier
info at startup.

Server: /api/backtest/{name}/recalc endpoint accepts ?fee_tier=X&staking_tier=Y
and returns recalculated PnL with the new fee structure. On-the-fly
recalculation — no need to re-run the backtest.

Dashboard: VIP tier dropdown (VIP 0-6) and staking tier dropdown
(None/Wood/Bronze/Silver/Gold/Platinum/Diamond) in backtest detail panel.
Changing either instantly recalculates PnL via the API.

Key finding: Cartea-Jaimungal goes from -5.58% net at VIP0 to +2.39% net
at VIP6+Diamond (maker rebate: exchange pays YOU -0.0024% to provide
liquidity). Fee structure completely changes strategy viability assessment.

config/fee_tiers.py

@@ -0,0 +1,91 @@
+"""
+Hyperliquid fee tiers — perps and spot, base rates + staking discounts.
+
+Source: https://hyperliquid.gitbook.io/hyperliquid-docs/trading/fees
+
+Fee = base_rate × staking_multiplier
+Staking tiers are based on staked HYPE tokens.
+"""
+
+from dataclasses import dataclass, field
+from typing import Optional
+
+# ── Perps fee tiers (base rates) ──
+PERPS_TIERS = {
+    0: {"name": "VIP 0", "volume": 0,         "taker": 0.00045, "maker": 0.00015},
+    1: {"name": "VIP 1", "volume": 5_000_000,  "taker": 0.00040, "maker": 0.00012},
+    2: {"name": "VIP 2", "volume": 25_000_000, "taker": 0.00035, "maker": 0.00008},
+    3: {"name": "VIP 3", "volume": 100_000_000,"taker": 0.00030, "maker": 0.00004},
+    4: {"name": "VIP 4", "volume": 250_000_000,"taker": 0.00025, "maker": 0.00000},
+    5: {"name": "VIP 5", "volume": 750_000_000,"taker": 0.00020, "maker": -0.00002},
+    6: {"name": "VIP 6", "volume": 2_500_000_000,"taker":0.00015,"maker": -0.00004},
+}
+
+# ── Spot fee tiers (base rates) ──
+SPOT_TIERS = {
+    0: {"name": "VIP 0", "volume": 0,          "taker": 0.00070, "maker": 0.00040},
+    1: {"name": "VIP 1", "volume": 100_000,     "taker": 0.00060, "maker": 0.00030},
+    2: {"name": "VIP 2", "volume": 1_000_000,   "taker": 0.00050, "maker": 0.00020},
+    3: {"name": "VIP 3", "volume": 10_000_000,  "taker": 0.00040, "maker": 0.00010},
+    4: {"name": "VIP 4", "volume": 50_000_000,  "taker": 0.00030, "maker": 0.00005},
+    5: {"name": "VIP 5", "volume": 200_000_000, "taker": 0.00020, "maker": 0.00000},
+    6: {"name": "VIP 6", "volume": 1_000_000_000,"taker":0.00010,"maker": -0.00005},
+}
+
+# ── Staking discount multipliers ──
+STAKING_TIERS = {
+    "none":     {"name": "No Stake", "multiplier": 1.00},
+    "wood":     {"name": "Wood",     "multiplier": 0.95},
+    "bronze":   {"name": "Bronze",   "multiplier": 0.90},
+    "silver":   {"name": "Silver",   "multiplier": 0.85},
+    "gold":     {"name": "Gold",     "multiplier": 0.80},
+    "platinum": {"name": "Platinum", "multiplier": 0.70},
+    "diamond":  {"name": "Diamond",  "multiplier": 0.60},
+}
+
+
+def effective_rate(base_rate: float, staking_tier: str = "none") -> float:
+    """Calculate effective fee rate after staking discount."""
+    mult = STAKING_TIERS.get(staking_tier, STAKING_TIERS["none"])["multiplier"]
+    return base_rate * mult
+
+
+def get_perp_fees(vip_tier: int, staking_tier: str = "none", fee_model: str = "taker") -> float:
+    """Get effective perp fee for a given VIP tier and staking tier."""
+    tier = PERPS_TIERS.get(vip_tier, PERPS_TIERS[0])
+    base = tier[fee_model] if fee_model in ("taker", "maker") else tier["taker"]
+    return effective_rate(base, staking_tier)
+
+
+def get_spot_fees(vip_tier: int, staking_tier: str = "none", fee_model: str = "taker") -> float:
+    """Get effective spot fee for a given VIP tier and staking tier."""
+    tier = SPOT_TIERS.get(vip_tier, SPOT_TIERS[0])
+    base = tier[fee_model] if fee_model in ("taker", "maker") else tier["taker"]
+    return effective_rate(base, staking_tier)
+
+
+def fee_tier_from_volume(volume_14d: float, market: str = "perps") -> int:
+    """Determine fee tier from 14-day rolling volume."""
+    tiers = PERPS_TIERS if market == "perps" else SPOT_TIERS
+    current = 0
+    for t in sorted(tiers.keys()):
+        if volume_14d >= tiers[t]["volume"]:
+            current = t
+    return current
+
+
+# ── Strategy-specific defaults (matching existing classification) ──
+STRATEGY_FEE_MODELS = {
+    "Order Book Imbalance": "taker",
+    "Iceberg Detection": "taker",
+    "Funding Rate Arb": "taker",
+    "Pairs Trading": "taker",
+    "Avellaneda-Stoikov": "maker",
+    "Momentum Breakout": "taker",
+    "Mean Reversion": "taker",
+    "Hawkes OFI": "taker",
+    "Deep LOB": "maker",
+    "Cartea-Jaimungal": "maker",
+    "Queue Imbalance": "taker",
+    "Guéant Market Making": "maker",
+}