fix(strategy-ui): correct rankings, currency, injection view and staleness

- MaxDD ranks shallower drawdowns first (values are negative); ruined
  results are badged and never ranked as best.
- Metrics render '—' for null/non-finite values instead of crashing.
- Amounts use the market's currency (CNY for CN) instead of hard-coded USD.
- Injection scenarios show invested / final value / profit / return on
  invested from capitalFlows and label return metrics as time-weighted.
- Precomputed results show their data end date and warn when older than 7
  days; live strategies warn when not updated for 4 days, show start date,
  price as-of, stale holdings, and same-window benchmark with excess return.
- Unknown precomputed scenario returns 400 instead of silently serving the
  first scenario; the client uses the scenarioId it receives.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

web/src/server/index.ts

@@ -172,6 +172,7 @@ function resolveScenarios(raw: { scenarios?: Record<string, unknown>; markets?:
       label: string;
       description?: string;
       capital: number;
+      capitalByMarket?: Record<string, number>;
       injectionSchedule: unknown;
       markets: Record<string, unknown>;
     }>;
@@ -191,6 +192,7 @@ function resolveScenarios(raw: { scenarios?: Record<string, unknown>; markets?:
       label: string;
       description?: string;
       capital: number;
+      capitalByMarket?: Record<string, number>;
       injectionSchedule: unknown;
       markets: Record<string, unknown>;
     }>;
@@ -207,6 +209,7 @@ app.get("/api/strategies/precomputed/index", (_request, response, next) => {
       label: sc.label,
       description: sc.description,
       capital: sc.capital,
+      capitalByMarket: sc.capitalByMarket,
       injectionSchedule: sc.injectionSchedule ?? null,
       availableMarkets: Object.keys(sc.markets ?? {}),
     }));
@@ -223,9 +226,12 @@ app.get("/api/strategies/precomputed", (_request, response, next) => {
     const raw = loadPrecomputedFile();
     const scenarios = resolveScenarios(raw);
     const scenarioIds = Object.keys(scenarios);
-    const scenarioId = requestedScenario && scenarios[requestedScenario]
-      ? requestedScenario
-      : scenarioIds[0];
+    // An explicit but unknown scenario is a client error; silently serving
+    // another scenario would mislabel the results.
+    if (requestedScenario && !Object.hasOwn(scenarios, requestedScenario)) {
+      throw new Error(`Unknown pre-computed scenario: ${requestedScenario}`);
+    }
+    const scenarioId = requestedScenario ?? scenarioIds[0];
     const scenario = scenarios[scenarioId];
     if (!scenario) {
       throw new Error("No pre-computed scenarios available.");