Fix AI model registry staleness on self-hosted instances (#19427)

## Summary

Fixes #19422.

Self-hosted users hitting "No AI models are available" after configuring
API keys via the admin panel were victims of a stale
`AiModelRegistryService` cache. Only the four `addAiProvider` /
`removeAiProvider` / `addModelToProvider` / `removeModelFromProvider`
mutations called `refreshRegistry()` — setting an API key through
`set/update/deleteDatabaseConfigVariable` left the registry pointing at
the pre-mutation provider state.

Rather than patch each mutation site (and re-introduce the same class of
bug on the next one), the registry now invalidates lazily based on the
LLM config-group hash, mirroring the pattern `WebSearchDriverFactory`
already uses via `DriverFactoryBase`. Any mutation to an LLM-tagged
config variable is picked up automatically on the next read — callers
never have to remember to refresh.

- Extracted `getConfigGroupHash` into a shared util reused by both
`DriverFactoryBase` and `AiModelRegistryService` (and switched the hash
to `JSON.stringify` so object-typed config vars like `AI_PROVIDERS`
actually contribute meaningfully).
- `AiModelRegistryService` gates all internal `Map` access behind
private getters that call `ensureFresh()`, so future read paths can't
accidentally observe stale state. Build path uses underscored backing
fields directly to avoid recursing.
- Dropped the now-redundant `refreshRegistry()` public method and its
four call sites in `admin-panel.resolver.ts`.

## Test plan

- [x] `nx typecheck twenty-server` passes
- [x] Existing admin-panel + ai-models specs pass (79 tests)
- [ ] Manual: on a self-hosted instance, set `OPENAI_API_KEY` (or
another provider key) via the admin panel `setDatabaseConfigVariable`
mutation and confirm AI features work without a server restart
- [ ] Manual: existing flows (`addAiProvider`, `addModelToProvider`,
etc.) still pick up new providers on the next read

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

packages/twenty-server/src/engine/core-modules/twenty-config/dynamic-factory.base.ts

@@ -1,15 +1,14 @@
-import { createHash } from 'crypto';
-
-import { ConfigVariables } from 'src/engine/core-modules/twenty-config/config-variables';
-import { type ConfigVariablesGroup } from 'src/engine/core-modules/twenty-config/enums/config-variables-group.enum';
+import { type ConfigGroupHashService } from 'src/engine/core-modules/twenty-config/services/config-group-hash.service';
 import { type TwentyConfigService } from 'src/engine/core-modules/twenty-config/twenty-config.service';
-import { TypedReflect } from 'src/utils/typed-reflect';
 
 export abstract class DriverFactoryBase<TDriver> {
   private currentDriver: TDriver | null = null;
   private currentConfigKey: string | null = null;
 
-  constructor(protected readonly twentyConfigService: TwentyConfigService) {}
+  constructor(
+    protected readonly twentyConfigService: TwentyConfigService,
+    protected readonly configGroupHashService: ConfigGroupHashService,
+  ) {}
 
   getCurrentDriver(): TDriver {
     let configKey: string;
@@ -43,31 +42,6 @@ export abstract class DriverFactoryBase<TDriver> {
     return this.currentDriver;
   }
 
-  protected getConfigGroupHash(group: ConfigVariablesGroup): string {
-    const groupVariables = this.getConfigVariablesByGroup(group);
-
-    const configValues = groupVariables
-      .map((key) => `${key}=${this.twentyConfigService.get(key)}`)
-      .sort()
-      .join('|');
-
-    return createHash('sha256')
-      .update(configValues)
-      .digest('hex')
-      .substring(0, 16);
-  }
-
-  private getConfigVariablesByGroup(
-    group: ConfigVariablesGroup,
-  ): Array<keyof ConfigVariables> {
-    const metadata =
-      TypedReflect.getMetadata('config-variables', ConfigVariables) ?? {};
-
-    return Object.keys(metadata)
-      .filter((key) => metadata[key]?.group === group)
-      .map((key) => key as keyof ConfigVariables);
-  }
-
   protected abstract buildConfigKey(): string;
   protected abstract createDriver(): TDriver;
 }

packages/twenty-server/src/engine/core-modules/twenty-config/services/config-group-hash.service.ts

@@ -0,0 +1,40 @@
+import { Injectable } from '@nestjs/common';
+
+import { createHash } from 'crypto';
+
+import { ConfigVariables } from 'src/engine/core-modules/twenty-config/config-variables';
+import { type ConfigVariablesGroup } from 'src/engine/core-modules/twenty-config/enums/config-variables-group.enum';
+import { TwentyConfigService } from 'src/engine/core-modules/twenty-config/twenty-config.service';
+import { TypedReflect } from 'src/utils/typed-reflect';
+
+@Injectable()
+export class ConfigGroupHashService {
+  constructor(private readonly twentyConfigService: TwentyConfigService) {}
+
+  computeHash(group: ConfigVariablesGroup): string {
+    const groupVariables = this.getConfigVariablesByGroup(group);
+
+    const configValues = groupVariables
+      .map(
+        (key) => `${key}=${JSON.stringify(this.twentyConfigService.get(key))}`,
+      )
+      .sort()
+      .join('|');
+
+    return createHash('sha256')
+      .update(configValues)
+      .digest('hex')
+      .substring(0, 16);
+  }
+
+  private getConfigVariablesByGroup(
+    group: ConfigVariablesGroup,
+  ): Array<keyof ConfigVariables> {
+    const metadata =
+      TypedReflect.getMetadata('config-variables', ConfigVariables) ?? {};
+
+    return Object.keys(metadata)
+      .filter((key) => metadata[key]?.group === group)
+      .map((key) => key as keyof ConfigVariables);
+  }
+}

packages/twenty-server/src/engine/core-modules/twenty-config/twenty-config.module.ts

@@ -3,6 +3,7 @@ import { type DynamicModule, Global, Module } from '@nestjs/common';
 import { ConfigVariables } from 'src/engine/core-modules/twenty-config/config-variables';
 import { CONFIG_VARIABLES_INSTANCE_TOKEN } from 'src/engine/core-modules/twenty-config/constants/config-variables-instance-tokens.constants';
 import { DatabaseConfigModule } from 'src/engine/core-modules/twenty-config/drivers/database-config.module';
+import { ConfigGroupHashService } from 'src/engine/core-modules/twenty-config/services/config-group-hash.service';
 import { ConfigurableModuleClass } from 'src/engine/core-modules/twenty-config/twenty-config.module-definition';
 import { TwentyConfigService } from 'src/engine/core-modules/twenty-config/twenty-config.service';
 
@@ -22,12 +23,13 @@ export class TwentyConfigModule extends ConfigurableModuleClass {
       imports,
       providers: [
         TwentyConfigService,
+        ConfigGroupHashService,
         {
           provide: CONFIG_VARIABLES_INSTANCE_TOKEN,
           useValue: new ConfigVariables(),
         },
       ],
-      exports: [TwentyConfigService],
+      exports: [TwentyConfigService, ConfigGroupHashService],
     };
   }
 }