fix: resolve all TypeScript type errors across codebase for Deno strict mode

Comprehensive type safety improvements across all CLI handlers and daemon:

**Error handling type fixes:**
- Add 'error instanceof Error' checks before accessing error.message throughout
- Fix all error/retryError/stdError/upsError type assertions
- Replace direct error.message with proper type guards

**Switch case improvements:**
- Wrap case block declarations in braces to satisfy deno-lint
- Fix no-case-declarations warnings in CLI command handlers

**Null/undefined safety:**
- Add checks for config.snmp and config.thresholds before access
- Fix IUpsStatus lastStatusChange to handle undefined with default value
- Add proper null checks in legacy configuration paths

**Type annotations:**
- Add explicit type annotations to lambda parameters (groupId, updateAvailable, etc.)
- Add TUpsModel type cast for 'cyberpower' default
- Import and use INupstConfig type where needed

**Parameter type fixes:**
- Fix implicit 'any' type errors in array callbacks
- Add type annotations to filter/find/map parameters

Files modified:
- ts/cli.ts: config.snmp/thresholds null checks, unused error variable fixes
- ts/cli/group-handler.ts: 4 error.message fixes + 2 parameter type annotations
- ts/cli/service-handler.ts: 3 error.message fixes
- ts/cli/ups-handler.ts: 5 error.message fixes + config checks + TUpsModel import
- ts/daemon.ts: 8 error.message fixes + IUpsStatus lastStatusChange fix + updateAvailable type
- ts/nupst.ts: 1 error.message fix
- ts/systemd.ts: 5 error.message fixes + parameter type annotation

All tests passing (3/3 SNMP tests + 10/10 logger tests)
Type check: ✓ No errors

ts/cli/group-handler.ts

@@ -78,7 +78,7 @@ export class GroupHandler {
       
       logger.logBoxEnd();
     } catch (error) {
-      logger.error(`Failed to list UPS groups: ${error.message}`);
+      logger.error(`Failed to list UPS groups: ${error instanceof Error ? error.message : String(error)}`);
     }
   }
   
@@ -187,7 +187,7 @@ export class GroupHandler {
         rl.close();
       }
     } catch (error) {
-      logger.error(`Add group error: ${error.message}`);
+      logger.error(`Add group error: ${error instanceof Error ? error.message : String(error)}`);
     }
   }
   
@@ -298,7 +298,7 @@ export class GroupHandler {
         rl.close();
       }
     } catch (error) {
-      logger.error(`Edit group error: ${error.message}`);
+      logger.error(`Edit group error: ${error instanceof Error ? error.message : String(error)}`);
     }
   }
   
@@ -375,7 +375,7 @@ export class GroupHandler {
       // Check if service is running and restart it if needed
       this.nupst.getUpsHandler().restartServiceIfRunning();
     } catch (error) {
-      logger.error(`Failed to delete group: ${error.message}`);
+      logger.error(`Failed to delete group: ${error instanceof Error ? error.message : String(error)}`);
     }
   }
 
@@ -485,7 +485,7 @@ export class GroupHandler {
       return;
     }
     
-    const group = config.groups.find(g => g.id === groupId);
+    const group = config.groups.find((g: { id: string }) => g.id === groupId);
     if (!group) {
       logger.error(`Group with ID "${groupId}" not found.`);
       return;
@@ -493,7 +493,7 @@ export class GroupHandler {
     
     // Show current assignments
     logger.log(`\nUPS devices in group "${group.name}" (${group.id}):`);
-    const upsInGroup = config.upsDevices.filter(ups => ups.groups && ups.groups.includes(groupId));
+    const upsInGroup = config.upsDevices.filter((ups: { groups?: string[] }) => ups.groups && ups.groups.includes(groupId));
     if (upsInGroup.length === 0) {
       logger.log('- None');
     } else {