Clean up hardcoded `"origin"` fallbacks and redundant `LoadConfig()` call

[alexrinass]

Six places fall back to a hardcoded "origin" string instead of relying solely on cfg.Remote (which already defaults to "origin" during config loading). One also makes a redundant LoadConfig() call just to get the remote name when cfg is already in scope. Behavior is currently correct, but the fallbacks are misleading and the extra LoadConfig() is wasteful.

Locations

Hardcoded "origin" fallback pattern (if remote == "" { remote = "origin" }):

• cmd/publish.go:93-94
• cmd/track.go:72-73
• cmd/delete.go:61-62
• cmd/delete.go:140-141
• cmd/update.go:141-142

Redundant LoadConfig() + "origin" fallback:

• cmd/finish.go:679-683 — handleCreateTagStep calls config.LoadConfig() to get the remote name, but cfg should be threaded through instead (same pattern PR Skip fetch when no remote is configured (#69) #74 fixes for handleDeleteBranchStep)

Suggested Fix

Remove all if remote == "" { remote = "origin" } fallbacks and use cfg.Remote directly. Thread cfg into handleCreateTagStep and remove the redundant LoadConfig() call.

Related: PR #74