Switch setup.ts to Alpine rootfs, fix remote deployment

- setup.ts now downloads Alpine Linux minirootfs instead of Ubuntu squashfs
- Installs Alpine packages (openssh, python3, curl, ca-certificates) in chroot
- Fixes install script failing on non-Alpine base rootfs (adduser syntax)
- Clean up unused imports and lint warnings

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/overseer.ts

@@ -147,7 +147,7 @@ export async function runOverseer(config: OverseerConfig) {
               );
               bot.say(event.target, `Models: ${lines.join(", ")}`);
             }
-          } catch (e) {
+          } catch {
             bot.say(event.target, "Error fetching models from Ollama.");
           }
           break;
@@ -189,7 +189,7 @@ export async function runOverseer(config: OverseerConfig) {
             } catch {}
 
             bot.say(event.target, `Agents: ${agents.length} running | Load: ${load} | RAM: ${freeMem}/${totalMem} GB free | Disk: ${diskFree} | Uptime: ${uptime}h | Ollama: ${ollamaModel}`);
-          } catch (e) {
+          } catch {
             bot.say(event.target, "Error getting status.");
           }
           break;