feat(label): add `ngit issue label` and `ngit pr label` commands

Publishes a NIP-32 kind-1985 label event referencing the target issue or
PR. Only the event author or a repository maintainer may apply labels.
Duplicate labels (already present via t-tags or prior kind-1985 events)
are silently skipped. The new event is saved to the local cache before
broadcasting so subsequent reads reflect the change immediately.

CLI:
  ngit issue label <id> --label <L> [--label <L>...]
  ngit pr label <id> --label <L> [--label <L>...]

1 files changed, 1 insertions, 0 deletions

diff --git a/src/bin/ngit/sub_commands/mod.rs b/src/bin/ngit/sub_commands/mod.rs
index c4d0821..7a3c2b5 100644
--- a/src/bin/ngit/sub_commands/mod.rs
+++ b/src/bin/ngit/sub_commands/mod.rs
@@ -7,6 +7,7 @@ pub mod init;
 pub mod issue_create;
 pub mod issue_list;
 pub mod issue_status;
+pub mod label;
 pub mod list;
 pub mod login;
 pub mod logout;