docs: version input streams under 4.4.2 and add docs site pages

Move input streams documentation from rules/4.3.0 to rules/4.4.2,
reverting 4.3.0 to its pre-input-streams state. Add comprehensive
input streams documentation to the Mintlify docs site with pages
for task-side usage, backend sending, and React hook patterns.

- rules/4.4.2/realtime.md: input streams docs (moved from 4.3.0)
- rules/manifest.json: add 4.4.2 version, revert 4.3.0 realtime
- docs/tasks/input-streams.mdx: main input streams guide
- docs/realtime/backend/input-streams.mdx: backend sending patterns
- docs/realtime/react-hooks/input-streams.mdx: React UI patterns
- docs/docs.json: add input streams to navigation
- Cross-references from existing streams and realtime overview docs

https://claude.ai/code/session_01SJHJts7r2yAxmoKLLz8vpc

Author: claude