feat(rust): RunicNPC as the Rust bundle's third artefact (runicnpc stage 4, D224)

The compose job carries the latest RunicNPC release that answers the API the
bridge's manifest declares (runicnpc_api), verified against its SHA256SUMS
like the other two; none when the bridge needs none, RunicNPC has not
released, or its API is too old, each said in the summary. Walked against a
mock Gitea in all three cases.

The installer reads the optional npc component (older bundles still parse),
fetches and checks RunicNPC's tarball against its manifest, places
RunicNPC.cs before the bridge in each instance's plugins directory, records
it, puts it back on update when edited or deleted, reports it in doctor, and
removes it on uninstall. Its data directory is never touched. Kits joins the
required plugins it reports.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

src/rustgame/uninstall.rs

@@ -62,6 +62,12 @@ pub fn run(cli: &Cli) -> Result<i32> {
         for helper in i.helpers.values() {
             println!("  · remove {}", helper.path);
         }
+        if let Some(npc) = &i.npc {
+            println!(
+                "  · remove {}  (RunicNPC; its placements in data/RunicNPC/ are kept)",
+                npc.path
+            );
+        }
         println!(
             "  · keep   {}  (the website's; it names this server)",
             i.plugin_config
@@ -114,6 +120,10 @@ pub fn run(cli: &Cli) -> Result<i32> {
         for helper in instance.helpers.values() {
             remove_file(Path::new(&helper.path), &mut done, &mut problems);
         }
+        // RunicNPC is the installer's file (D224); its data directory is the admins', and stays.
+        if let Some(npc) = &instance.npc {
+            remove_file(Path::new(&npc.path), &mut done, &mut problems);
+        }
         remove_file(Path::new(&instance.plugin_path), &mut done, &mut problems);
         if cli.purge {
             remove_file(Path::new(&instance.config_path), &mut done, &mut problems);