feat(data-model): custom-indexes management UI and mutations (#20846)

## Summary

Brings indexes management into the per-object Settings tab as a section
under Search (no feature flag, advanced mode only). Admins can create /
delete non-unique indexes with the UI; apps can declare indexes in code
with `defineIndex`. Composite-typed fields are now indexable by picking
a specific sub-column (e.g. `Address > City`).

A few related polish items also land here (invite-user dropdown lands on
the Invite tab; standard warning callout above the new-index form).

## What ships

### UI — custom indexes on per-object Settings
- New section directly under Search, wrapped in
`AdvancedSettingsWrapper`.
- Filter dropdown on the search bar toggles system-index visibility
(shown by default since advanced mode).
- **+ Add Index** button (disabled with tooltip once the per-object cap
is reached) navigates to a dedicated `SettingsObjectNewIndex` page
(matches the field-creation pattern, not a modal):
- Field picker mirrors the webhook event-form layout (rows of dropdowns,
implicit trailing empty row).
- Composite fields surface their sub-properties (`Address > City`,
`Currency > Amount`, …).
  - BTREE / GIN type selector.
- Standard warning Callout: "Use indexes sparingly — each one speeds
reads but slows writes."
- Trash icon on `isCustom: true` rows → confirmation modal →
`deleteOneIndex`.

### Server — `createOneIndex` / `deleteOneIndex` mutations
- Gated by `SettingsPermissionGuard(DATA_MODEL)`.
- `IndexMetadataService` wraps the existing migration runner via
`WorkspaceMigrationValidateBuildAndRunService` so the metadata row and
the SQL index land atomically.
- Validation: rejects empty fields, duplicate `(fieldMetadataId,
subFieldName)` pairs, fields not on the object, requires `subFieldName`
for composite parents, forbids `subFieldName` on scalar/relation,
enforces `MAX_CUSTOM_INDEXES_PER_OBJECT = 10`.
- Delete refuses on `isCustom: false` rows so system indexes can't be
removed via this API.
- Dedicated GraphQL exception handler maps each typed error to the right
transport error class.

### Composite sub-field indexing
- Adds `subFieldName: string | null` column to
`IndexFieldMetadataEntity` (fast instance command).
- The flat-entity flow (`UniversalFlatIndexFieldMetadata`,
`FlatIndexFieldMetadata`, `from-universal-flat-index-to-flat-index`,
runner column resolution) all carry `subFieldName` through.
- For composite parents, the runner uses
`computeCompositeColumnName({...}, property)` for the picked sub-column;
for non-composite parents, behavior is unchanged.
- The `'::'` separator encodes `(fieldMetadataId, subFieldName)` for
dedup on the wire; the frontend uses the same separator inside the
Select component's string value.

### Apps can declare indexes in code (`defineIndex`)
- New `IndexManifest` + `IndexFieldManifest` types in
`twenty-shared/application` wired into the `Manifest` type.
- `defineIndex` SDK helper + `IndexConfig`. CLI manifest builder +
extractor recognize `defineIndex` / `ManifestEntityKey.Indexes`.
- Server: `from-index-manifest-to-universal-flat-index` converter
resolves field IDs, validates composite/scalar `subFieldName` rules, and
delegates to `generateFlatIndexMetadataWithNameOrThrow` for the
deterministic name.
- Orchestrator wires the loop after the field-resolution pass;
per-object cap enforced inline against the manifest.
- Cascade on uninstall is automatic — when an app disappears its indexes
drop with it (universal-flat-entity diff handles it).
- Rich-app fixture ships a real `defineIndex` on `PostCard.status`,
exercising the full manifest → install path in CI.

### Closed for now (open later if needed)
- Apps cannot declare `isUnique` indexes — unique constraints stay with
the field-creation flow.
- Apps cannot use a partial-`indexWhereClause` — the UI surface keeps
the framework's hardcoded allowlist.
- UI cannot create unique or partial indexes either; same reasons.

### Cleanups along the way
- Reused the existing `getCompositeSubFieldLabel` +
`COMPOSITE_FIELD_SUB_FIELD_LABELS` (deleted the duplicates I'd created
early in the PR).
- Moved `MAX_CUSTOM_INDEXES_PER_OBJECT` to `twenty-shared/constants`
(single source for FE + BE).
- Replaced inline `isDefined(x) && x !== ''` with `isNonEmptyString`
(from `@sniptt/guards`).
- Hoisted the per-object fields Map + inlined the cap counter into the
indexes orchestrator loop (drops the install scan from O(indexes ×
totalFields) to O(totalFields + indexes)).
- Per design-feedback: page-based create flow (not a modal), filter
dropdown on the SearchInput (not a separate toggle), webhook-style
picker, field icons.

### Unrelated polish that lands here
- "Invite user" link in the multi-workspace dropdown now lands on the
Invite tab directly (`#invite`) instead of the first tab of the members
page.

## Test plan
- [ ] `npx nx typecheck twenty-server / twenty-front / twenty-sdk /
twenty-shared` — passes
- [ ] `npx nx lint:diff-with-main twenty-server / twenty-front` — clean
- [ ] `npx jest index-metadata.service.spec` — green
- [ ] `npx jest from-index-manifest-to-universal-flat-index` — green
(new converter spec, 8 cases)
- [ ] `npx vitest run
src/sdk/define/indexes/__tests__/define-index.spec.ts` (twenty-sdk) —
green (6 cases)
- [ ] `npx vitest run --config vitest.integration.config.ts -t
"rich-app"` — green (rich-app app-dev integration exercises the new
manifest path with the PostCard.status index)
- [ ] Advanced mode → Settings → any object → Settings tab → Indexes
section is visible under Search
- [ ] Create a single-field BTREE index, confirm SQL index exists
(verify via `pg_indexes`)
- [ ] Create a composite-field index (`Address > City`) and confirm the
column is `addressAddressCity`
- [ ] Create an index spanning two columns; column order matches the
picker order
- [ ] Attempt to create an 11th custom index → button is disabled with
tooltip
- [ ] Delete a custom index → confirmation modal → row disappears, PG
index dropped
- [ ] System indexes have no trash icon and are hidden by default

packages/twenty-client-sdk/src/metadata/generated/schema.ts

@@ -386,6 +386,7 @@ export interface IndexField {
     id: Scalars['UUID']
     fieldMetadataId: Scalars['UUID']
     order: Scalars['Float']
+    subFieldName?: Scalars['String']
     createdAt: Scalars['DateTime']
     updatedAt: Scalars['DateTime']
     __typename: 'IndexField'
@@ -2742,6 +2743,8 @@ export interface Mutation {
     createOneObject: Object
     deleteOneObject: Object
     updateOneObject: Object
+    createOneIndex: Index
+    deleteOneIndex: Index
     createOneAgent: Agent
     updateOneAgent: Agent
     deleteOneAgent: Agent
@@ -3257,6 +3260,7 @@ export interface IndexFieldGenqlSelection{
     id?: boolean | number
     fieldMetadataId?: boolean | number
     order?: boolean | number
+    subFieldName?: boolean | number
     createdAt?: boolean | number
     updatedAt?: boolean | number
     __typename?: boolean | number
@@ -5795,6 +5799,8 @@ export interface MutationGenqlSelection{
     createOneObject?: (ObjectGenqlSelection & { __args: {input: CreateOneObjectInput} })
     deleteOneObject?: (ObjectGenqlSelection & { __args: {input: DeleteOneObjectInput} })
     updateOneObject?: (ObjectGenqlSelection & { __args: {input: UpdateOneObjectInput} })
+    createOneIndex?: (IndexGenqlSelection & { __args: {input: CreateOneIndexInput} })
+    deleteOneIndex?: (IndexGenqlSelection & { __args: {input: DeleteOneIndexInput} })
     createOneAgent?: (AgentGenqlSelection & { __args: {input: CreateAgentInput} })
     updateOneAgent?: (AgentGenqlSelection & { __args: {input: UpdateAgentInput} })
     deleteOneAgent?: (AgentGenqlSelection & { __args: {input: AgentIdInput} })
@@ -6126,6 +6132,18 @@ id: Scalars['UUID']}
 
 export interface UpdateObjectPayload {labelSingular?: (Scalars['String'] | null),labelPlural?: (Scalars['String'] | null),nameSingular?: (Scalars['String'] | null),namePlural?: (Scalars['String'] | null),description?: (Scalars['String'] | null),icon?: (Scalars['String'] | null),shortcut?: (Scalars['String'] | null),color?: (Scalars['String'] | null),isActive?: (Scalars['Boolean'] | null),labelIdentifierFieldMetadataId?: (Scalars['UUID'] | null),imageIdentifierFieldMetadataId?: (Scalars['UUID'] | null),isLabelSyncedWithName?: (Scalars['Boolean'] | null),isSearchable?: (Scalars['Boolean'] | null)}
 
+export interface CreateOneIndexInput {
+/** The custom index to create */
+index: CreateIndexInput}
+
+export interface CreateIndexInput {objectMetadataId: Scalars['UUID'],fields: CreateIndexFieldInput[],indexType: IndexType}
+
+export interface CreateIndexFieldInput {fieldMetadataId: Scalars['UUID'],subFieldName?: (Scalars['String'] | null)}
+
+export interface DeleteOneIndexInput {
+/** The id of the custom index to delete. */
+id: Scalars['UUID']}
+
 export interface CreateAgentInput {name?: (Scalars['String'] | null),label: Scalars['String'],icon?: (Scalars['String'] | null),description?: (Scalars['String'] | null),prompt: Scalars['String'],modelId: Scalars['String'],roleId?: (Scalars['UUID'] | null),responseFormat?: (Scalars['JSON'] | null),modelConfiguration?: (Scalars['JSON'] | null),evaluationInputs?: (Scalars['String'][] | null)}
 
 export interface UpdateAgentInput {id: Scalars['UUID'],name?: (Scalars['String'] | null),label?: (Scalars['String'] | null),icon?: (Scalars['String'] | null),description?: (Scalars['String'] | null),prompt?: (Scalars['String'] | null),modelId?: (Scalars['String'] | null),roleId?: (Scalars['UUID'] | null),responseFormat?: (Scalars['JSON'] | null),modelConfiguration?: (Scalars['JSON'] | null),evaluationInputs?: (Scalars['String'][] | null)}