fix: Phase 2 QA — all 25 remaining HIGH/MEDIUM/LOW issues

HIGH fixes (7):
- H1: VNCdirectory admin i18n — 30+ translation keys added
- H2: handleSave try/catch with error toast
- H3: Free/busy accountId scoping
- H4: cancelEventBookings filter by eventId
- H5: Resource picker static apiFetch import
- H6: Sharing-store toast messages via lastMessage state
- H7: roleLabel for all resource types

MEDIUM fixes (11):
- M1: identitySignatureMap cleanup on delete
- M2: Now-line relative positioning
- M3: Radial menu disabled item keyboard nav
- M4: Radial menu stable event listener via refs
- M5: cancelBooking error on missing booking
- M6: PasswordRow isMasked state flag
- M7: Extract shared rights into lib/sharing-rights.ts
- M8: VNCtalk client server-side guard
- M9: Collabora configManager instead of process.env
- M10: CONFIG_ENV_MAP VNCdirectory fields
- M11: SENSITIVE_CONFIG_KEYS field name unification

LOW fixes (7):
- L1-L3: Unused imports removed
- L4: aria-labels on close, clear, search, spinner
- L5-L7: Comments for intentional patterns, null guard

lib/eml-import.ts

@@ -17,10 +17,6 @@ function isTgzName(name: string): boolean {
   return /\.(tgz|tar\.gz)$/i.test(name);
 }
 
-function isArchiveName(name: string): boolean {
-  return isZipName(name) || isTgzName(name);
-}
-
 async function extractEmlsFromZip(file: File): Promise<ImportableEmail[]> {
   const { default: JSZip } = await import("jszip");
   const zip = await JSZip.loadAsync(await file.arrayBuffer());