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/jmap/client.ts

@@ -4957,12 +4957,13 @@ export class JMAPClient implements IJMAPClient {
   async queryAllCalendarEvents(
     filter: CalendarEventFilter,
     sort?: Array<{ property: string; isAscending: boolean }>,
-    limit?: number
+    limit?: number,
+    accountId?: string
   ): Promise<CalendarEvent[]> {
     try {
       const allEvents: CalendarEvent[] = [];
       const primaryId = this.getCalendarsAccountId();
-      const accountIds = this.getCalendarCapableAccountIds();
+      const accountIds = accountId ? [accountId] : this.getCalendarCapableAccountIds();
 
       for (const accountId of accountIds) {
         const isPrimary = accountId === primaryId;