feat: trade mandate (budget + horizon) wired end-to-end

- database.py: add trade_budget_eur / preferred_horizon_min/max config
  defaults and include them in cycle config migrations
- auto_cycle.py: read trade params from config and inject into cycle_meta
- ai_analyzer.py: inject INVESTOR TRADE MANDATE block into scoring and
  suggestion prompts so GPT-4o penalises horizon mismatches and sizes
  within the capital cap
- Config.tsx: Trade Parameters card with budget + horizon sliders and live
  mandate summary
- TradeIdeas.tsx: horizon filter pills (< 1M / 1-3M / 3-6M / > 6M) and
  budget/horizon indicator pulled from saved config
- useApi.ts: extend useUpdateCycleConfig type with new config fields

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/Config.tsx

@@ -430,6 +430,9 @@ export default function Config() {
   const [cycleSimilarity, setCycleSimilarity] = useState(0.30)
   const [minEv, setMinEv] = useState(0.0)
   const [minScore, setMinScore] = useState(0)
+  const [tradeBudget, setTradeBudget] = useState(5000)
+  const [horizonMin, setHorizonMin] = useState(30)
+  const [horizonMax, setHorizonMax] = useState(180)
   const [retentionDays, setRetentionDays] = useState(90)
   const [maturityThreshold, setMaturityThreshold] = useState(35)
   const [weekendEnabled, setWeekendEnabled] = useState(true)
@@ -441,6 +444,9 @@ export default function Config() {
       setCycleSimilarity(cs.similarity_threshold ?? 0.30)
       setMinEv(cs.min_ev_threshold ?? 0.0)
       setMinScore(cs.min_score_threshold ?? 0)
+      setTradeBudget(cs.trade_budget_eur ?? 5000)
+      setHorizonMin(cs.preferred_horizon_min ?? 30)
+      setHorizonMax(cs.preferred_horizon_max ?? 180)
       setRetentionDays(cs.journal_retention_days ?? 90)
       setMaturityThreshold(cs.maturity_threshold_pct ?? 35)
       setWeekendEnabled(cs.weekend_cycle_enabled ?? true)
@@ -725,6 +731,63 @@ export default function Config() {
             </div>
           </div>
 
+          {/* Trade Parameters */}
+          <div className="card">
+            <h2 className="text-base font-bold text-white flex items-center gap-2 mb-1">
+              <DollarSign className="w-4 h-4 text-emerald-400" /> Trade Parameters
+            </h2>
+            <p className="text-xs text-slate-500 mb-4">
+              Passed into every AI cycle — controls capital sizing and filters out patterns outside your investment horizon.
+            </p>
+            <div className="grid grid-cols-1 gap-6 md:grid-cols-3">
+              <div>
+                <label className="text-xs text-slate-500 mb-2 block">
+                  Simulation budget: <span className="text-emerald-400 font-mono font-bold">€{tradeBudget.toLocaleString()}</span>
+                </label>
+                <input type="range" min="500" max="50000" step="500"
+                  value={tradeBudget}
+                  onChange={e => setTradeBudget(parseInt(e.target.value))}
+                  className="w-full accent-emerald-500" />
+                <div className="flex justify-between text-[10px] text-slate-600 mt-1">
+                  <span>€500</span><span>€50,000</span>
+                </div>
+                <div className="text-xs text-slate-500 mt-1">
+                  Max per position: <span className="text-slate-300 font-mono">€{Math.round(tradeBudget * 0.25).toLocaleString()}</span> (25%)
+                </div>
+              </div>
+              <div>
+                <label className="text-xs text-slate-500 mb-2 block">
+                  Min horizon: <span className="text-blue-400 font-mono font-bold">{horizonMin}d</span>
+                </label>
+                <input type="range" min="1" max="90" step="1"
+                  value={horizonMin}
+                  onChange={e => setHorizonMin(Math.min(parseInt(e.target.value), horizonMax - 5))}
+                  className="w-full accent-blue-500" />
+                <div className="flex justify-between text-[10px] text-slate-600 mt-1">
+                  <span>1d</span><span>90d</span>
+                </div>
+                <div className="text-xs text-slate-500 mt-1">Patterns shorter than {horizonMin}d penalized in R/R</div>
+              </div>
+              <div>
+                <label className="text-xs text-slate-500 mb-2 block">
+                  Max horizon: <span className="text-blue-400 font-mono font-bold">{horizonMax}d</span>
+                </label>
+                <input type="range" min="30" max="365" step="5"
+                  value={horizonMax}
+                  onChange={e => setHorizonMax(Math.max(parseInt(e.target.value), horizonMin + 5))}
+                  className="w-full accent-blue-500" />
+                <div className="flex justify-between text-[10px] text-slate-600 mt-1">
+                  <span>30d</span><span>365d</span>
+                </div>
+                <div className="text-xs text-slate-500 mt-1">Patterns longer than {horizonMax}d penalized in R/R</div>
+              </div>
+            </div>
+            <div className="mt-4 p-3 rounded bg-emerald-900/10 border border-emerald-700/20 text-xs text-emerald-300">
+              Active mandate: budget <span className="font-mono">€{tradeBudget.toLocaleString()}</span> · horizon{' '}
+              <span className="font-mono">{horizonMin}–{horizonMax}d</span> · AI will size + filter suggestions accordingly
+            </div>
+          </div>
+
           {/* Auto-Cycle settings */}
           <div className="card">
             <div className="flex items-center justify-between mb-4">
@@ -901,6 +964,9 @@ export default function Config() {
                     similarity_threshold: cycleSimilarity,
                     min_ev_threshold: minEv,
                     min_score_threshold: minScore,
+                    trade_budget_eur: tradeBudget,
+                    preferred_horizon_min: horizonMin,
+                    preferred_horizon_max: horizonMax,
                     journal_retention_days: retentionDays,
                     maturity_threshold_pct: maturityThreshold,
                     weekend_cycle_enabled: weekendEnabled,