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, 10 insertions, 0 deletions

diff --git a/src/bin/ngit/main.rs b/src/bin/ngit/main.rs
index 6a5a8f0..b0cf375 100644
--- a/src/bin/ngit/main.rs
+++ b/src/bin/ngit/main.rs
@@ -130,6 +130,11 @@ async fn main() {
                     squash,
                     offline,
                 } => sub_commands::pr_merge::launch(id, *squash, *offline).await,
+                PrCommands::Label {
+                    id,
+                    labels,
+                    offline,
+                } => sub_commands::label::launch_pr_label(id, labels, *offline).await,
             },
             Commands::Issue(args) => match &args.issue_command {
                 IssueCommands::List {
@@ -193,6 +198,11 @@ async fn main() {
                     )
                     .await
                 }
+                IssueCommands::Label {
+                    id,
+                    labels,
+                    offline,
+                } => sub_commands::label::launch_issue_label(id, labels, *offline).await,
             },
             Commands::Sync(args) => sub_commands::sync::launch(args).await,
         }