feat(pvisor): integrate ZCode CLI

[zhaoyuuu0624]

Support pvisor run -- zcode with staged project edits, persistent login/session state, and Gateway & overlaynet capture.

• Inject ZCode proxy settings and provide an opt-in BigModel individual-account profile without changing saved credentials.
• Fix gzip/deflate response decoding in Gateway (Zcode from BigModel version), which caused 502 errors during title generation and memory extraction. Add regression tests and a real-CLI integration example.

Host networking remains cooperative; persistent state is outside apply/drop. API-key providers require explicit routing. External proxy chaining is outside this PR.

Validation

• Build and formatting checks, all 338 Gateway tests, and the added ZCode/configuration tests passed on macOS.
• Current commit 45267dc passed live macOS ZCode testing with BigModel API-key routing: all five model requests returned 200, including title generation and memory extraction. Verified staged writes, selective apply, and drop of the remaining file. The automatic account-provider profile was not exercised.
• Linux ZCode interaction, staging and apply/drop passed with existing proxy support; the extracted commits have not been rerun on Linux as my linux server's network is different.