fix(cli): bound example archive download time

[RerankerGuo]

Description

memos download_examples downloaded the GitHub archive without a timeout. A stalled connection could therefore block the CLI indefinitely.

This change applies the same bounded-network behavior used elsewhere in the client: the archive request now times out after 30 seconds. The extraction behavior and destination layout are unchanged.

Related Issue (Required): N/A — regression reproduced on current main.

Type of change

• Bug fix (non-breaking)

How Has This Been Tested?

• Before: the focused test expected timeout=30 and failed with actual call requests.get(url).
• After: .venv/bin/pytest tests/test_cli.py -q (6 passed).
• Ruff check and format pass for both changed files.

Impact

• Breaking change: no
• Scope: CLI example archive download only
• Dependencies: none

[Memtensor-AI]

🤖 Open Code Review

Target: PR #2216
Task: cd827644b6e5388c
Base: main
Head: fix/cli-download-examples-timeout

✅ OpenCodeReview: No comments generated. Looks good to me.

Generated by cloud-assistant via Open Code Review.

[Memtensor-AI]

✅ Automated Test Results: PASSED

All tests passed (6/6 executed). memos_python_core/changed-repo-python: 6/6. Duration: 5s [advisory, non-gating] AI-generated tests on branch test/auto-gen-cd827644b6e5388c-20260805142955: 20/21 passed, 1 failed — these do NOT affect the PR verdict; review the branch manually.

Branch: fix/cli-download-examples-timeout