refactor: standardize AI acronym to Ai (PascalCase) across internal identifiers (#19837)

## Summary

The "AI" acronym was rendered inconsistently across the codebase. The
backend AI module had settled on PascalCase `Ai` (`AiAgentModule`,
`AiBillingService`, `AiChatModule`, `AiModelRegistryService`, etc.),
while frontend components, several DTOs, a few types, and shared
identifiers still used all-caps `AI` (`AIChatTab`,
`AISystemPromptPreviewDTO`, `SettingsPath.AIPrompts`, ...). CLAUDE.md
specifies PascalCase for classes; this PR normalizes everything internal
to `Ai`.

**This is a pure internal rename.** The GraphQL schema is untouched —
`@ObjectType` decorator string arguments, resolver method names (which
become Query/Mutation field names), gql template contents, and the
`generated-metadata/graphql.ts` file are preserved verbatim. The only
visible change is TypeScript identifiers and file names.

## Also folded in (adjacent cleanups)

- **`AgentModelConfigService` → `AiModelConfigService`**. Lives in
`ai-models/` and is used by multiple AI code paths, not just the Agent
entity. The "Agent" prefix was misleading.
- **`generate-text-input.dto.ts` → `generate-text.input.ts`**. The
`ai-agent/dtos/` folder already uses `<entity>.input.ts` convention for
Input classes (`create-agent.input.ts` etc.); the old path mixed
`.dto.ts` file extension with a class that has no DTO suffix. File
rename only; class stays `GenerateTextInput`.
- **Removed stale TODO** in `ai-model-config.type.ts` that asked for the
`AiModelConfig` rename that this PR performs.

## Rename methodology

Bulk rename via perl with anchored regex
`(?<!['"])(?<![A-Z.])AI([A-Z])(?=[a-z])/Ai$1/g`:

- **Lookbehind for non-uppercase** skips adjacent acronyms (`MOSAIC`,
`OIDCSSO`) and leaves `AIRBNB_ID` alone.
- **Lookbehind for non-quote** protects most string literals.
- **Lookahead for lowercase** restricts matches to PascalCase
identifiers (`AIChatTab`), leaving SCREAMING_SNAKE constants untouched.

Strict file-scope exclusions: `generated-metadata/**`, `generated/**`,
`locales/**`, `migrations/**`, `illustrations/**`, `halftone/**`, and
the two gql template files (`queries/getAISystemPromptPreview.ts`,
`mutations/uploadAIChatFile.ts`).

Post-rename reverts for identifiers where the regex was too eager:
- Backend resolver method names kept: `getAISystemPromptPreview`,
`uploadAIChatFile` (they are GraphQL field names).
- `@ObjectType('AdminAIModels')` / `('AISystemPromptPreview')` /
`('AISystemPromptSection')` kept as-is.
- Backend classes `ClientAIModelConfig` / `AdminAIModelConfig` kept
as-is (they use `@ObjectType()` with no argument, so the class name IS
the schema name).
- External-library symbols restored: `OpenAIProvider`,
`createOpenAICompatible`, `vercelAIIntegration`.

File renames use a two-step rename to work on macOS case-insensitive
filesystems: `git mv X.tsx X.tsx.tmp && git mv X.tsx.tmp renamed.tsx`.

## Diff audit

- 0 changes to migrations
- 0 changes to locale `.po` / `.ts` files
- 0 changes to `generated-metadata/graphql.ts`
- 0 changes to website illustration files (base64 blobs preserved)
- 0 renames inside user-facing translation strings (`t\`…\``,
`msg\`…\``, `<Trans>…</Trans>`)

## Test plan

- [x] `npx nx typecheck twenty-server` — PASS
- [x] `npx nx typecheck twenty-front` — PASS
- [x] `npx jest ai-model admin agent-role` — 79/79 PASS
- [x] `npx oxlint --type-aware` on 118 changed files — 0 errors
- [x] `npx prettier --check` on 118 changed files — clean
- [ ] CI

packages/twenty-front/src/modules/ai/components/AgentChatThreadInitializationEffect.tsx

@@ -10,8 +10,8 @@ import { agentChatInputState } from '@/ai/states/agentChatInputState';
 import { agentChatThreadsLoadingState } from '@/ai/states/agentChatThreadsLoadingState';
 import { agentChatThreadsSelector } from '@/ai/states/agentChatThreadsSelector';
 import { agentChatUsageComponentFamilyState } from '@/ai/states/agentChatUsageComponentFamilyState';
-import { currentAIChatThreadState } from '@/ai/states/currentAIChatThreadState';
-import { currentAIChatThreadTitleComponentFamilyState } from '@/ai/states/currentAIChatThreadTitleComponentFamilyState';
+import { currentAiChatThreadState } from '@/ai/states/currentAiChatThreadState';
+import { currentAiChatThreadTitleComponentFamilyState } from '@/ai/states/currentAiChatThreadTitleComponentFamilyState';
 import { hasInitializedAgentChatThreadsState } from '@/ai/states/hasInitializedAgentChatThreadsState';
 import { hasTriggeredCreateForDraftState } from '@/ai/states/hasTriggeredCreateForDraftState';
 import { useUpdateMetadataStoreDraft } from '@/metadata-store/hooks/useUpdateMetadataStoreDraft';
@@ -35,14 +35,14 @@ export const AgentChatThreadInitializationEffect = () => {
     PermissionFlagType.AI_SETTINGS,
   );
 
-  const currentAIChatThread = useAtomStateValue(currentAIChatThreadState);
-  const setCurrentAIChatThread = useSetAtomState(currentAIChatThreadState);
+  const currentAiChatThread = useAtomStateValue(currentAiChatThreadState);
+  const setCurrentAiChatThread = useSetAtomState(currentAiChatThreadState);
   const setAgentChatInput = useSetAtomState(agentChatInputState);
   const setAgentChatThreadsLoading = useSetAtomState(
     agentChatThreadsLoadingState,
   );
   const threadTitleFamilyCallback = useAtomComponentFamilyStateCallbackState(
-    currentAIChatThreadTitleComponentFamilyState,
+    currentAiChatThreadTitleComponentFamilyState,
   );
   const agentChatUsageFamilyCallback = useAtomComponentFamilyStateCallbackState(
     agentChatUsageComponentFamilyState,
@@ -93,7 +93,7 @@ export const AgentChatThreadInitializationEffect = () => {
   useEffect(() => {
     if (
       hasInitializedAgentChatThreads ||
-      (currentAIChatThread !== null && isValidUuid(currentAIChatThread))
+      (currentAiChatThread !== null && isValidUuid(currentAiChatThread))
     ) {
       return;
     }
@@ -114,7 +114,7 @@ export const AgentChatThreadInitializationEffect = () => {
       const draftForThread =
         store.get(agentChatDraftsByThreadIdState.atom)[firstThread.id] ?? '';
 
-      setCurrentAIChatThread(firstThread.id);
+      setCurrentAiChatThread(firstThread.id);
       setAgentChatInput(draftForThread);
 
       const firstThreadFamilyKey = { threadId: firstThread.id };
@@ -144,7 +144,7 @@ export const AgentChatThreadInitializationEffect = () => {
       );
     } else {
       store.set(hasTriggeredCreateForDraftState.atom, false);
-      setCurrentAIChatThread(AGENT_CHAT_NEW_THREAD_DRAFT_KEY);
+      setCurrentAiChatThread(AGENT_CHAT_NEW_THREAD_DRAFT_KEY);
       setAgentChatInput(
         store.get(agentChatDraftsByThreadIdState.atom)[
           AGENT_CHAT_NEW_THREAD_DRAFT_KEY
@@ -153,12 +153,12 @@ export const AgentChatThreadInitializationEffect = () => {
     }
   }, [
     agentChatThreads,
-    currentAIChatThread,
+    currentAiChatThread,
     hasAiSettingsPermission,
     hasInitializedAgentChatThreads,
     setHasInitializedAgentChatThreads,
     storeEntry.status,
-    setCurrentAIChatThread,
+    setCurrentAiChatThread,
     setAgentChatInput,
     store,
     threadTitleFamilyCallback,