perf: fix N+1 query pattern across all modules + rack numbering

CRITICAL PERF BUG: Every hook did storage.list() (1 HTTP call fetching ALL
items with values, discarding values, returning only keys) then storage.get()
for EACH key (N individual HTTP calls re-fetching values one by one).

With 6 entries + contacts + tags, Registratura page fired ~40 sequential
HTTP requests on load, where 3 would suffice.

Fix: Replace list()+N*get() with single exportAll() call in ALL hooks:
- registratura/registry-service.ts (added exportAll to RegistryStorage interface)
- address-book/use-contacts.ts
- it-inventory/use-inventory.ts
- password-vault/use-vault.ts
- word-templates/use-templates.ts
- prompt-generator/use-prompt-generator.ts
- hot-desk/use-reservations.ts
- email-signature/use-saved-signatures.ts
- digital-signatures/use-signatures.ts
- ai-chat/use-chat.ts
- core/tagging/tag-service.ts (uses storage.export())

Additional fixes:
- registratura/use-registry.ts: addEntry uses optimistic local state update
  instead of double-refresh; closeEntry batches saves with Promise.all +
  single refresh
- server-rack.tsx: reversed slot rendering so U1 is at bottom (standard
  rack numbering, per user's physical rack)

Performance impact: ~90% reduction in HTTP requests on page load for all modules

src/modules/prompt-generator/hooks/use-prompt-generator.ts

@@ -1,39 +1,42 @@
-'use client';
+"use client";
 
-import { useState, useCallback, useMemo, useEffect } from 'react';
-import { useStorage } from '@/core/storage';
-import { v4 as uuid } from 'uuid';
-import type { PromptTemplate, PromptHistoryEntry, OutputMode } from '../types';
-import { BUILTIN_TEMPLATES } from '../services/builtin-templates';
-import { composePrompt } from '../services/prompt-composer';
+import { useState, useCallback, useMemo, useEffect } from "react";
+import { useStorage } from "@/core/storage";
+import { v4 as uuid } from "uuid";
+import type { PromptTemplate, PromptHistoryEntry, OutputMode } from "../types";
+import { BUILTIN_TEMPLATES } from "../services/builtin-templates";
+import { composePrompt } from "../services/prompt-composer";
 
-const HISTORY_PREFIX = 'history:';
-const TEMPLATE_PREFIX = 'template:';
+const HISTORY_PREFIX = "history:";
+const TEMPLATE_PREFIX = "template:";
 
 export function usePromptGenerator() {
-  const storage = useStorage('prompt-generator');
-  const [selectedTemplate, setSelectedTemplate] = useState<PromptTemplate | null>(null);
+  const storage = useStorage("prompt-generator");
+  const [selectedTemplate, setSelectedTemplate] =
+    useState<PromptTemplate | null>(null);
   const [values, setValues] = useState<Record<string, unknown>>({});
   const [customTemplates, setCustomTemplates] = useState<PromptTemplate[]>([]);
   const [history, setHistory] = useState<PromptHistoryEntry[]>([]);
   const [loading, setLoading] = useState(true);
 
-  const allTemplates = useMemo(() => [...BUILTIN_TEMPLATES, ...customTemplates], [customTemplates]);
+  const allTemplates = useMemo(
+    () => [...BUILTIN_TEMPLATES, ...customTemplates],
+    [customTemplates],
+  );
 
   // Load custom templates and history
   useEffect(() => {
     async function load() {
       setLoading(true);
-      const keys = await storage.list();
+      const all = await storage.exportAll();
       const templates: PromptTemplate[] = [];
       const entries: PromptHistoryEntry[] = [];
-      for (const key of keys) {
+      for (const [key, value] of Object.entries(all)) {
+        if (!value) continue;
         if (key.startsWith(TEMPLATE_PREFIX)) {
-          const t = await storage.get<PromptTemplate>(key);
-          if (t) templates.push(t);
+          templates.push(value as PromptTemplate);
         } else if (key.startsWith(HISTORY_PREFIX)) {
-          const h = await storage.get<PromptHistoryEntry>(key);
-          if (h) entries.push(h);
+          entries.push(value as PromptHistoryEntry);
         }
       }
       entries.sort((a, b) => b.createdAt.localeCompare(a.createdAt));
@@ -59,7 +62,7 @@ export function usePromptGenerator() {
   }, []);
 
   const composedPrompt = useMemo(() => {
-    if (!selectedTemplate) return '';
+    if (!selectedTemplate) return "";
     return composePrompt(selectedTemplate, values);
   }, [selectedTemplate, values]);
 
@@ -74,7 +77,10 @@ export function usePromptGenerator() {
       composedPrompt,
       outputMode: selectedTemplate.outputMode,
       providerProfile: selectedTemplate.providerProfile ?? null,
-      safetyBlocks: selectedTemplate.safetyBlocks?.filter((s) => s.enabled).map((s) => s.id) ?? [],
+      safetyBlocks:
+        selectedTemplate.safetyBlocks
+          ?.filter((s) => s.enabled)
+          .map((s) => s.id) ?? [],
       tags: selectedTemplate.tags,
       isFavorite: false,
       createdAt: new Date().toISOString(),
@@ -84,10 +90,13 @@ export function usePromptGenerator() {
     return entry;
   }, [storage, selectedTemplate, values, composedPrompt]);
 
-  const deleteHistoryEntry = useCallback(async (id: string) => {
-    await storage.delete(`${HISTORY_PREFIX}${id}`);
-    setHistory((prev) => prev.filter((h) => h.id !== id));
-  }, [storage]);
+  const deleteHistoryEntry = useCallback(
+    async (id: string) => {
+      await storage.delete(`${HISTORY_PREFIX}${id}`);
+      setHistory((prev) => prev.filter((h) => h.id !== id));
+    },
+    [storage],
+  );
 
   const clearSelection = useCallback(() => {
     setSelectedTemplate(null);