feat!: add 'gra fetch', remove 'gra clean' and 'gra migrate'

[martinus]

Fetching was hidden inside gra clean, so the one command that went to the network was the one about removing worktrees, while gra ls — whose SYNC column the fetch is for — stayed offline with no way to refresh it.

gra fetch (new)

Runs git fetch --prune --all in every repository under the gra root, several at a time:

Fetching 14 repositories
fetched 14 repositories

• Every remote, not just origin: a fork's upstream is exactly the remote that goes stale.
• Only remote-tracking refs move — no worktree, branch, or uncommitted change is touched.
• A repository that cannot be reached is named with git's reason and the others are still fetched (fetched 13 of 14 repositories).
• gra ls --fetch fetches first and then prints the table, so SYNC is current.

gra clean removed

gra done removes a worktree with the same merged / patch-equivalent checks, one at a time and where you are standing. That takes the .grakeep keep marker with it — nothing reads it any more, so it is no longer written to the local exclude file. Existing repositories keep the now-inert exclude line; an existing .grakeep file will start showing up as untracked.

gra migrate removed

It renamed worktrees named by gra 1.x–3.x, which have all been renamed by now. The dead is_generated_name/WORD_LENGTH helpers go with it.

Net: -373 lines. Five new tests cover fetch + prune across repositories, the second remote, an unreachable repository not costing the others their fetch, the empty root, and ls --fetch refreshing SYNC.

🤖 Generated with Claude Code