agentbridge: Homebrew tap (espetro/homebrew-tap) with agentbridge.rb formula

[espetro]

Context

New repo espetro/homebrew-tap with Formula/agentbridge.rb. Formula downloads the right GitHub Release tarball, verifies SHA256, symlinks to /opt/homebrew/bin/.

Tasks

• Create espetro/homebrew-tap repo
• Write Formula/agentbridge.rb with class Agentbridge
• Formula downloads tarball, verifies SHA256, installs binary
• Add CI to open a PR bumping the formula on each release
• brew install espetro/tap/agentbridge works on macOS + Linux

Source

• New repo: espetro/homebrew-tap
• homebrew-tap/Formula/agentbridge.rb
• Plan: .agents/plans/2026-06-14-v0.2.0-distribution-pivot.md