fix(market-data): hot-reload provider + credentials when config changes

[luokerenx4]

Summary

Changing `marketData.providers` via the UI had no effect — every `/api/market-data-v1/*` request kept resolving to the provider that was live at server boot, because the resolver closure and the `defaultCredentials` value were both snapshotted at `mountOpenTypeBB` time, and `ctx.config` itself is never reassigned when the config-write route persists edits to disk (only the Telegram / MCP-Ask reconnect path was wired to the PUT handler, and it doesn't touch opentypebb).

Three mechanical changes close the loop:

• opentypebb `mountToHono`'s `defaultCredentials` widens to `value | null | (() => value | null)` and re-evaluates the getter on each request, mirroring the `resolveProvider` callback that was already lazy.
• Alice's mount helper (`src/server/opentypebb.ts`) accepts static values or getters for both `defaultProviders` and `defaultCredentials`; the resolver reads via getter per request.
• web-plugin passes closures that read `ctx.config.marketData.{providers,providerKeys}` per invocation.
• config PUT route (`routes/config.ts`): after `writeConfigSection`, reload the full config and `Object.assign` onto `ctx.config` so in-memory state stays in sync with disk. Preserves `ctx.config`'s object identity.

TODO.md gets an Architecture entry flagging this as a band-aid — three different config-sync strategies now coexist (connector reconnect, opentypebb lazy getter + Object.assign, sub-reference capture that just goes stale), and the right fix is a unified pub/sub config bus plus a file watcher for out-of-band edits. Worth one focused pass next time something goes stale.

Test plan

• `npx tsc --noEmit` clean
• `pnpm test` — 1088 tests / 56 files pass
• Live flip without restart: `PUT /api/config/marketData` with `providers.equity = 'fmp'` → next `/api/market-data-v1/equity/price/quote` returns `provider: fmp`; flip back to `yfinance` → returns `yfinance`. Both directions, zero restart.
• Credentials path: adding an FMP API key via UI takes effect on the next request to an FMP-gated endpoint.

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