Add screenpipe to context engineering systems

[louis030195]

Adds screenpipe to Context Engineering Systems & Kits in both the English and Chinese READMEs.

screenpipe is a direct context-engineering input layer: it captures real work context across screen, audio, input, browser, and meetings, then exposes searchable evidence to agents through MCP, REST, and CLI.

The wording explicitly says source-available and avoids describing the current license as open source. Placement follows the section star ordering using the current 19.9k GitHub star count.

Disclosure: I maintain screenpipe.

Validation:

• both language files contain exactly one matching entry
• git diff --check
• repository, website, and documentation links return HTTP 200