mdz_stream_parser_url.ts
Auto-URL and auto-path handlers (text-first scanning) for the streaming mdz parser. Operates in two phases:
1. Speculative prefix matching: chars stream as visible text while we
verify a https:// / http:// prefix.
2. Confirmed mode: chars stream as text and on terminator a wrap
opcode retroactively wraps the text node in a Link.
Paths (/..., ./..., ../...) skip phase 1 — their prefix is validated
by hold (require enough lookahead).