fix: add missing shutil import in setup.py (fixes #5060)

[Sertug17]

Problem

When running hermes setup with E2EE enabled, the setup wizard crashes at
line 2126 of setup.py with NameError: name 'shutil' is not defined.

This happens because:

1. matrix-nio[e2e] fails to import (ModuleNotFoundError)
2. The except handler tries to locate uv via shutil.which("uv")
3. But shutil was never imported at the module level — only locally
   inside other functions (lines 951, 1397, 1513)

Fix

Add import shutil at the top of hermes_cli/setup.py alongside the
other standard library imports.

Fixes #5060

[trevorgordon981]

Correct one-line fix for a real crash path — NameError: name 'shutil' is not defined when E2EE setup's except handler tries shutil.which("uv").

Two of the local import shutil calls inside other functions (lines 1121 and 1308 on current main) become redundant after this PR — Python resolves the module-level import first. Not a blocker, but worth cleaning up either now or in a follow-up so there's one import location and new contributors don't wonder why shutil is imported three times in one file.

# hermes_cli/setup.py now has:
# line ~17: import shutil   (this PR — good)
# line 1121: import shutil  (redundant, dead-ish import)
# line 1308: import shutil  (redundant, dead-ish import)

ruff's F811 (redefined-while-unused) catches this pattern if the linter config includes it.

Ship it — fixes the actual crash. The redundant-import cleanup can happen whenever someone touches those functions next.

[Sertug17]

Thanks for the review! Agreed on the redundant imports — happy to clean those up in this PR if preferred, rather than waiting for a follow-up.

@trevorgordon981 I see you've opened #5136 — should I incorporate that cleanup here, or would you prefer to keep them separate?

[teknium1]

Merged via PR #5271 using #5136's implementation (which includes a regression test). Your fix was identical and correct — both contributors credited. Thanks!