No supported way to open a file in a GUI app on the user's behalf (open -e fails with procNotFound)

**Summary**

Attempting `open -e file.txt` (or `open -t`) to hand the user a local file in their default text editor / TextEdit fails with `procNotFound: no eligible process with specified descriptor`, regardless of sandbox state. This looks like a genuine capability gap rather than a permission to grant — the Bash tool's subprocess appears to have no route into the user's actual logged-in GUI/desktop session at all, so any `open`-style "launch an app for the user" command is a dead end.

**Impact**

Minor but recurring: there's no way for an agent to say "I've opened this for you to look at" for a native file the way it can hand over a file via other mechanisms. The closest alternative delivers a file to the user but doesn't open a specific native app with it.

**Reproduction**

1. In a Claude Code session on macOS, run `open -e `.
2. Observe `procNotFound: no eligible process with specified descriptor` (or equivalent), independent of `dangerouslyDisableSandbox`.

**Suggested fix**

Either document this explicitly as unsupported (so agents stop attempting it and burning a turn on it), or provide a supported mechanism for handing a file to the user's default or chosen application.

Start by reproducing in a Claude Code session on macOS with `open -e ` and noting the `procNotFound` failure. The issue names no files or tests and leaves the fix open between documentation and a new supported mechanism, so done means maintainers first decide which direction is wanted and the resulting behavior or docs make this unsupported path explicit.

索引モデルが issue の本文から書いたものです。