Implements hs-tokens-of, hs-stream-token, hs-stream-consume,
hs-stream-has-more, hs-token-type, hs-token-value, hs-token-op?,
hs-raw->api-token, hs-eof-sentinel in runtime.sx.
Tokenizer emits whitespace tokens after the first content token;
stream functions skip them for look-ahead and consume. Parser
filters whitespace tokens at hs-parse entry. Dot/hash after close
brackets split into PERIOD/POUND + IDENTIFIER. Template escape \$
produces literal $.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>