fix(update): switch to main before pulling local-only branches

[SollanSystems]

Summary

• keep current_branch separate from the update target branch in cmd_update
• when the current branch does not exist on origin, explicitly git checkout main before git pull --ff-only origin main
• restore any autostashed local changes even if the fallback checkout fails
• add regression coverage for checkout-before-pull and stash restore on checkout failure

Problem

Updating from a local-only branch could fall back to main logically, but still attempt to fast-forward from the local branch context. That leads to update failures like:

fatal: Not possible to fast-forward, aborting.

Test Plan

• uv run --extra dev pytest -o addopts= tests/hermes_cli/test_cmd_update.py tests/hermes_cli/test_update_autostash.py tests/hermes_cli/test_update_gateway_restart.py tests/hermes_cli/test_update_check.py -q

[Copilot]

Pull request overview

This PR fixes hermes update failures when run from a local-only git branch by ensuring the update pull happens from the correct checked-out branch, and adds regression tests around branch switching and autostash restoration behavior.

Changes:

• Track current_branch separately from the update target branch in cmd_update.
• When the current branch is not present on origin, checkout main before git pull --ff-only origin main.
• Ensure autostashed changes are restored even if the fallback checkout fails; add regression tests for these behaviors.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
hermes_cli/main.py	Separates current vs target branch and checks out the target branch (e.g., main) before pulling to avoid FF-only failures from local-only branches.
tests/hermes_cli/test_cmd_update.py	Adds regression tests verifying checkout happens before pull on fallback, and that stashed changes are restored even when checkout fails.

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[Copilot]

This assertion hard-codes git_cmd as ["git"], but cmd_update uses a platform-dependent git_cmd (on Windows it becomes ["git", "-c", "windows.appendAtomically=false"]). Consider asserting the git_cmd argument more flexibly (e.g., match the prefix, or derive the expected value from sys.platform) so the test remains portable if run on Windows.

[teknium1]

Thanks for the fix! This was independently addressed in PR #3492 (merged March 27), which did a broader hardening of hermes update — it now unconditionally targets main and switches branches before pulling, with stash/restore handling. Your fix is correct but already covered.