Keep preset sessions resumable after preflight errors

[SiluPanda]

Summary

• resolve caller-local preset environment inputs before creating or mutating a creation session
• leave an interrupted session unchanged when resume preflight fails, so the caller can fix the environment and retry
• avoid creating an orphaned failed session when the same preflight check fails for a fresh creation

The existing exception handling still marks failures from the actual creation workflow as terminal. Only errors that occur before that workflow starts now leave session state untouched.

Fixes #4164.

Validation

$ uv run pytest -q src/tests/_internal/cli/services/presets/test_create.py
63 passed in 1.60s

$ uv run ruff format --check <changed Python files>
2 files already formatted

$ uv run ruff check <changed Python files>
All checks passed!

$ git diff --check
# no output

AI-assisted implementation; I reviewed the diff and ran the checks above locally.