Add of(...) convenience factory to StockQuotesRequest and OptionsQuotesRequest #17

Every request type in the SDK exposes a paired construction surface:

• Foo.of(required...) — convenience factory, required args only, all optionals defaulted
• Foo.builder(required...) — full builder for setting optionals

Two multi-symbol request types are missing the of(...) half of that pair — they only have builder(...):

• StockQuotesRequest — StockQuotesRequest.java:31 has builder(String first, String... rest), no of(...)
• OptionsQuotesRequest — OptionsQuotesRequest.java:39 has builder(String first, String... rest), no of(...)

The varargs sibling StockPricesRequest already has both (StockPricesRequest.java:20), so this is an accidental omission, not a deliberate design choice. A consumer wanting a no-options multi-symbol quote is forced into .builder(...).build() for no reason.

Proposed change

Add a matching convenience factory to both types, mirroring StockPricesRequest.of:

public static StockQuotesRequest of(String first, String... rest) {
    return builder(first, rest).build();
}

public static OptionsQuotesRequest of(String first, String... rest) {
    return builder(first, rest).build();
}

Why now

The API-section docs (MarketDataApp/documentation#154) are standardizing on convenience factories so the Java/Kotlin examples read in 1–3 lines. These two endpoints currently cannot use that pattern and are stuck showing StockQuotesRequest.builder("AAPL", "META", "MSFT").build(). Adding of(...) lets the docs go minimal:

client.stocks().quotes(StockQuotesRequest.of("AAPL", "META", "MSFT")).values().forEach(System.out::println);

Acceptance

• StockQuotesRequest.of(String first, String... rest) added
• OptionsQuotesRequest.of(String first, String... rest) added
• Unit tests cover the new factories (parity with StockPricesRequest test coverage)
• No other request type is missing its of(...) pair (sweep to confirm this is the last gap)