Closes security loopholes and updates docs:
- installs seccomp filter for blocking naughty syscalls
- tightens macos seatbelt profile
- fetch tool responses that redirect are now constrained by allowed
domains list

Also adds a few "Learn More" buttons that link to the new docs.

Also fixes a bug where the agent would try to create a
`~/.config/zed/AGENTS.md` directory

Also adds unicode confusable detection to URL/path privilege escalation
prompts.

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Release Notes:

- N/A or Added/Fixed/Improved ...

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Co-authored-by: zed-zippy[bot] <234243425+zed-zippy[bot]@users.noreply.github.com>