feat(browser): complete interactive shell demos

[NathanFlurry]

Summary

• run real Brush, Vim, Git, Bash, and core WASM commands through AgentOS VFS/PTY execution in both the Actor API and browser-local terminal demos
• add the minimal Browserbase CDP shell experiment, with raw terminal bytes over CDP and a persistent Cloudflare tunnel for the remote browser
• converge browser execution on the generated native V8 bridge and shared builtin/WASI surfaces instead of demo-specific command dispatch
• fix interactive PTY behavior: ordered terminal output, exact termios restoration after Vim, resize/SIGWINCH delivery, shebang execution, and real Brush child PIDs
• preserve complete software packages when skip-mode staging overlays a partial native command target

Root cause

• browser child processes could reuse parent-local WASI descriptor numbers, and command execution was selected from a host basename map instead of executable bytes resolved from the guest VFS
• Actor stdout and stderr were broadcast by independent tasks, while shared-PTY children could leave inherited terminal state behind after full-screen execution
• Brush's WASM adapter discarded the virtual PID already returned by AgentOS, causing WARN could not retrieve pid for child process
• skip-mode software staging deleted the existing bin/ before discovering that a partial native target did not contain every declared command

Validation

• cargo check --workspace
• pnpm --dir packages/runtime-browser test — 136 tests
• pnpm --dir packages/agentos-toolchain test — 19 passed, 2 skipped
• pnpm --dir packages/build-tools test
• focused native PTY discipline regression
• browser-terminal E2E — Actor API and browser-local shell/Vim/script/Git/Pi workflows both passed; screenshots captured under ~/progress/agent-os/2026-07-13-dual-terminal-vim-git/
• Browserbase E2E session 02562fcd-fd33-4a07-8972-d6fcd94adbd0 — shell, Ctrl-C, redirects, Vim-authored executable script, Git commit/rev-parse, and no PID warning
• scripts/verify-fixed-versions.mjs

Browserbase credentials remain explicit environment variables; the experiment never reads a developer-local credentials file.

[railway-app]

🚅 Deployed to the agentos-pr-1745 environment in agentos

Service	Status	Web	Updated (UTC)
agentos	😴 Sleeping (View Logs)	Web	Jul 14, 2026 at 3:59 pm

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🚅 Environment agentos-pr-1745 in rivet-frontend has no services deployed.