chore(lint): enable strict ESLint rules and fix unused-vars violations (F4.1)

Enable no-console (warn, allow error), @typescript-eslint/no-unused-vars
(warn, ignore _ prefix), and @typescript-eslint/no-explicit-any (warn).
Fix all 26 no-unused-vars violations across 9 files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/composables/useCategoryEditGuard.ts

@@ -57,7 +57,7 @@ export function useCategoryEditGuard (config: GuardConfig) {
           : 0
 
       linkedCount.value = extractTotal(result.data, fallbackLength)
-    } catch (error) {
+    } catch (_error) {
       linkedCount.value = 0
     } finally {
       linkedLoading.value = false

app/composables/useMachineHierarchy.ts

@@ -4,7 +4,7 @@
  * Extracted from pages/machine/[id].vue to keep the page orchestrator lean.
  */
 
-import { resolveIdentifier, resolveProductReference, getProductDisplay } from '~/shared/utils/productDisplayUtils'
+import { resolveIdentifier, getProductDisplay } from '~/shared/utils/productDisplayUtils'
 import { resolveConstructeurs, uniqueConstructeurIds, type ConstructeurSummary } from '~/shared/constructeurUtils'
 
 type AnyRecord = Record<string, unknown>

app/composables/useMachinePrint.ts

@@ -6,7 +6,6 @@
 
 import { ref, reactive, nextTick } from 'vue'
 import { buildMachinePrintContext, buildMachinePrintHtml } from '~/utils/printTemplates/machineReport'
-import { resolveIdentifier } from '~/shared/utils/productDisplayUtils'
 
 type AnyRecord = Record<string, unknown>