feat(PR): track all branch merges

[mikewuu]

Currently Homie only tracks default branch merges. e.g., merges to develop. Sometimes users want to know which PRs were merged to which branch.

This task is to also save/track merges to other branches.

Requirements

• [x] store source_branch and target_branch name
• [x] add is_default_branch_merge
• [x] Update list merges to filter by default only summary only sends default
• [x] save all open/merged prs
• [x] Only embed default branch merges to avoid duplicate data
• [x] Update review table to show branch it was merged to only show default merges here
• [x] Update AI tool to be able to filter by target branch name (getListPullRequestsTool)