Teach IPv6 notation and separate language API guides

[jrepp]

The documentation previously mixed an address-format reference with installation and API details. Rewrite the entry page as an IPv6 introduction that explains hexadecimal groups, zero compression, prefixes, common addresses, ports, zone IDs, and embedded IPv4 through worked examples and expandable practice questions.

Move API usage into separate C, JavaScript, and TypeScript guides, with a development page for builds, testing, and publishing. Share the documentation stylesheet and navigation, and update the README, demo, and existing guides to link to the new pages.

Validation:

• Compiled and ran the C examples against the native library.
• Ran the JavaScript and TypeScript examples; TypeScript uses strict application checking with the documented skipLibCheck workaround for existing package declaration conflicts.
• Checked 106 local links, Pages links, assets, and anchors, plus the introductory address expansions.
• Checked all five documentation pages at mobile and desktop widths in light and dark themes.
• Verified navigation, expandable answers, demo links, and the standalone browser WebAssembly example without browser exceptions.
• git diff --check passed.

The TypeScript guide documents existing declaration/runtime differences. This change does not modify the parser or its declarations.