* feature: add webull brokerage core integration
- add BrokerageName.Webull enum value
- add WebullBrokerageModel supporting Equity, Option, IndexOption
- add WebullFeeModel with zero commission for equity/option, tiered index option fees (SPX, SPXW, VIX/VIXW, XSP, DJX, NDX/NDXP), 0.6% crypto fee
- register Webull in IBrokerageModel factory switch and GetBrokerageName
- add webull config keys and live-webull environment to Launcher/config.json
- add WebullBrokerageModelTests (CanSubmitOrder, GetFeeModel)
- add WebullFeeModelTests covering all index option tiers and crypto
* refactor: split webull supported order types per security type
- replace flat _supportSecurityTypes/_supportOrderTypes with _supportedOrderTypesBySecurityType dictionary
- options and index options: Limit, StopMarket, StopLimit only
- equity, future, crypto: Market, Limit, StopMarket, StopLimit, TrailingStop
- add WebullOrderProperties with OutsideRegularTradingHours flag
- add messages for unsupported order type validation
* fix: add market order type to option and index option supported orders
* chore: add webull crypto symbols to symbol-properties-database
* test: consolidate webull fee model and brokerage model tests
- merge per-tier and per-symbol [Test] methods into [TestCase]/[TestCaseSource] parameterized tests in WebullFeeModelTests
- replace CreateIndexOptionSecurity/CreateOptionSecurity/CreateCryptoSecurity with single CreateSecurity(SecurityType, decimal, string) helper
- rename test methods to PascalCase (drop underscores) in WebullBrokerageModelTests
- remove section-separator comments from WebullBrokerageModelTests
- update Launcher/config.json for local Webull UAT environment
* remove: restriction GTC for Option and Buy side only
* refactor: limit webull to equity and options
- remove crypto and future support from order types and tests
- remove crypto fee logic and crypto symbol-properties rows
- reject market orders with outsideRth on equity
- log info when market order uses non-day tif
