feat: add ngit issue list command

Non-interactive listing of NIP-34 issues (kind 1621) with status
resolution, hashtag display, and detail view.

- get_issues_from_cache: fetch GitIssue events from local cache by repo
  coordinate, mirroring get_proposals_and_revisions_from_cache
- ngit issue list: table output of ID, status, title and hashtags at end
  of each row; status resolved via existing get_status() logic
- --status: comma-separated filter (open,draft,closed,applied; default: open)
- --hashtag: comma-separated label filter (case-insensitive, OR match)
- --json: machine-readable output including hashtags and description
- --offline: skip network fetch, use local cache only
- <id>: optional positional argument (hex event-id or nevent) to show
  full details of a specific issue including body content

1 files changed, 30 insertions, 0 deletions

diff --git a/src/bin/ngit/cli.rs b/src/bin/ngit/cli.rs
index 68b18a7..c2364e6 100644
--- a/src/bin/ngit/cli.rs
+++ b/src/bin/ngit/cli.rs
@@ -134,6 +134,8 @@ pub enum Commands {
         #[arg(long)]
         offline: bool,
     },
+    /// list issues
+    Issue(IssueSubCommandArgs),
     /// checkout a proposal branch by event-id or nevent
     #[command(
         long_about = "checkout a proposal branch by event-id or nevent\n\nuse `ngit list` to find proposal IDs"
@@ -195,6 +197,34 @@ pub struct RepoSubCommandArgs {
     pub offline: bool,
 }
 
+#[derive(clap::Parser)]
+pub struct IssueSubCommandArgs {
+    #[command(subcommand)]
+    pub issue_command: IssueCommands,
+}
+
+#[derive(Subcommand)]
+pub enum IssueCommands {
+    /// list issues and their statuses
+    List {
+        /// Filter by status (comma-separated: open,draft,closed,applied)
+        #[arg(long, default_value = "open")]
+        status: String,
+        /// Filter by hashtag/label (comma-separated)
+        #[arg(long)]
+        hashtag: Option<String>,
+        /// Output as JSON
+        #[arg(long)]
+        json: bool,
+        /// Show details for a specific issue (event-id or nevent)
+        #[arg(value_name = "ID|nevent")]
+        id: Option<String>,
+        /// Use local cache only, skip network fetch
+        #[arg(long)]
+        offline: bool,
+    },
+}
+
 #[derive(Subcommand)]
 pub enum RepoCommands {
     /// publish a repository to nostr (alias for `ngit init`)