feat: allow bundling small related issues into a single branch/PR

[q-soriarty]

Description

The current git-workflow skill strictly requires one branch per issue and one PR per issue. In practice, when multiple small, closely related issues belong to the same feature area and have no independent value, forcing separate branches adds overhead without benefit.

Proposed Change

Allow bundling 2-3 small related issues into a single branch and PR when:

• The issues belong to the same command group or feature area
• Each issue is small (< 30 min implementation)
• They share no dependencies with other work
• They would be reviewed together anyway

The PR should reference all closed issues (Closes #X, Closes #Y, Closes #Z) and the description should clearly separate each issue's contribution.

Example

We encountered this building copia-cli. Phase 3 had three small issues:

• docs: clarify semver impact for revert commit type (#18) #22 — copia org list/view (2 files)
• docs: document GitHub auto-close limitation with non-default branch merges #23 — copia notification list/read (2 files)
• docs: document GitHub auto-close limitation with non-default branch merges (#23) #24 — copia completion bash/zsh/fish/powershell (1 file)

Each was ~15 min TDD work, all registered in the same root command, no interdependency. Creating 3 separate branches, 3 PRs, 3 CI runs, 3 merge cycles added significant ceremony for trivial changes.

The bundled approach: one branch with 4 atomic commits (one per issue + wiring), one PR with all 3 Closes references, one review cycle.

Suggested Skill Update

Add a note in the "Issue-Driven Workflow" section:

Small issue bundling: When 2-3 issues are small, closely related, and belong to the same feature area, they may be implemented on a single branch with one PR. Each issue should have its own atomic commit(s), and the PR must reference all closed issues. Use judgment — if any issue could reasonably be reviewed independently, keep it separate.