fix: keep tool child stdin closed and run tool commands non-interactively

[utk-code]

Issue for this PR

Closes #42773

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

On Windows, tool commands that prompt on stdin (e.g. npm exec asking "Ok to proceed? (y)") hang — the prompt shows but nothing typed reaches the process, because the child stdin is an open pipe nothing closes and the TUI owns the console input.

Changes:

• Spawner default for child stdin changed from open pipe to closed ("ignore"). Callers passing explicit stdin are unaffected.
• Shell/bash tool commands now get CI=1, npm_config_yes=true, GIT_TERMINAL_PROMPT=0, NONINTERACTIVE=1, so tools like npm skip interactive prompts.

How did you verify your code works?

Reproduced on Windows: npm exec with an open stdin pipe hangs; with CI=1 or npm_config_yes=true it completes. Checked no tests rely on the old default.

Screenshots / recordings

N/A (not a UI change)

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

Hey! Your PR title Fix tool interactive stdin doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[Enough1122]

AI code review — automated review for reference; please use your judgment.

Review of the non-interactive tool execution fix:

1. packages/core/src/cross-spawn-spawner.ts:119 — the default stdin flips from pipe to ignore for every caller that does not pass opts.stdin — any call site relying on the old implicitly-writable pipe (e.g. feeding data or credentials to a child) now gets an instantly-closed stdin and can fail or hang confusingly — audit internal callers for stdin writes, make the new expectation explicit at those sites, and call the semantic change out in release notes.
2. packages/core/src/tool/bash.ts:162 and packages/opencode/src/tool/shell.ts:294 — the non-interactive env quartet (CI, npm_config_yes, GIT_TERMINAL_PROMPT, NONINTERACTIVE) is defined twice across two packages — duplicate literals drift apart the first time one copy gains DEBIAN_FRONTEND=noninteractive and the other does not — extract a shared exported constant (e.g. from core) and import it in both places.
3. packages/core/src/tool/bash.ts:162 and packages/opencode/src/tool/shell.ts:298 — npm_config_yes=true makes package installs auto-confirm inside agent-executed shells — it prevents hangs, but it also silently removes the confirmation step for actions like npm install -g that the model initiates — document this contract in the bash/shell tool descriptions, or scope auto-yes to non-global installs.
4. packages/opencode/src/tool/shell.ts:297-308 — nonInteractiveEnv is spread last, so it overrides explicitly provided env — sessions that deliberately set CI=0 or a custom GIT_TERMINAL_PROMPT are silently clobbered — either let per-command env take precedence over the defaults or add a comment marking the override as intentional hardening.
5. Test coverage — neither behavior change ships with tests — add cases asserting a spawned child sees immediate EOF on stdin and that all four env vars are present on both the POSIX and win32 code paths.
6. packages/core/src/cross-spawn-spawner.ts:119 — encoding: "utf-8" is retained next to stream: "ignore" — dead config that misleads readers into thinking output transcoding still applies — drop it for the ignore case or comment why it stays.