Function matchTag

matchTag(tag: string, range: string): boolean
Checks if a language tag matches a language range.

Implements Extended Filtering per RFC 4647 § 3.3.2. Matching is case-insensitive and compares subtags sequentially:
- Wildcard * in range matches any subtag sequence
- Singleton subtags (single character) in tag block further matching
- Range subtags must appear in order, but tag may have additional subtags between matches
Parameters
- tag: string
  The language tag to test
- range: string
  The language range to match against
Returns boolean
true if the tag matches the range pattern
Example
```
import { matchTag, asTag, asTagRange } from "@metreeca/core";

matchTag(asTag("de-DE"), asTagRange("de-*-DE"));        // true
matchTag(asTag("de-Latn-DE"), asTagRange("de-*-DE"));   // true
matchTag(asTag("de"), asTagRange("de-*-DE"));           // false - missing 'DE'
matchTag(asTag("de-x-DE"), asTagRange("de-*-DE"));      // false - singleton 'x' blocks
```
See
- Defined in src/network/language.ts:281