feat: introduce index layout skill for FULL_PAGE index/list tables

- Added a new skill for managing index and list table layouts in the ERP project, detailing layout and data contracts.
- Updated project guidelines to reference the new index layout skill.
- Introduced rules for page composition, column definitions, audit fields, action column width, and toolbar functionality.
- Created utility functions for computing action column width and formatting audit fields, along with corresponding unit tests to ensure reliability.

These changes enhance the application by providing a structured approach to index layouts, improving consistency and usability across the ERP project.

.cursor/rules/web-design-layout.mdc

@@ -27,6 +27,7 @@ Reference usage: `apps/showcase` (ui-components, forms, action-tools, shell-demo
 
 Detail **content** layout (section stack, key-value grids, status blocks, tabs for many categories): follow `.agents/skills/detail-layout/SKILL.md` — layout/position only.
 Form **content** layout: follow `.agents/skills/form-layout/SKILL.md`.
+Index / list layout (toolbar, action column, audit columns): follow `.agents/skills/index-layout/SKILL.md`.
 Entities with `latitude` / `longitude`: follow `web-location-maps.mdc` — form must pick coords on `LocationMap`; detail must render `LocationMap`.
 
 Every page header (`pageHeaderProps`) should include i18n `title`, `description`, `breadcrumbs`, and Lucide `icon` when useful.

.cursor/rules/web-index-table.mdc

@@ -0,0 +1,33 @@
+---
+description: Index / list table contracts for FULL_PAGE modules (actions, audit columns, reload)
+globs: apps/web/src/apps/**/*.page.index.tsx,packages/ui/src/foundations/enterprise-module/components/data-table/**
+alwaysApply: false
+---
+
+# Web Index Table
+
+Index pages: `EnterpriseIndexPageProvider` + `EnterpriseDataTable`. Do not rebuild the toolbar or default columns. Full layout: `.agents/skills/index-layout/SKILL.md`.
+
+## Module columnDefs
+
+Business fields only. Do **not** redeclare action, status, or audit columns.
+
+```tsx
+// GOOD
+<EnterpriseDataTable columnDefs={[{ field: 'code' }, { field: 'name' }]} filterConfig={filterConfig} />
+
+// BAD — duplicates shared prefix/postfix
+columnDefs={[{ colId: 'action_column', width: 180 }, { field: 'created_at' }]}
+```
+
+## Audit fields
+
+Transformers map camelCase: `createdBy`, `createdAt`, `updatedBy`, `updatedAt`. The shared table postfix binds those names (with snake_case fallback). Do not emit `creator_name` / `created_at` in TrackGo transformers.
+
+## Action column
+
+Width is computed in `EnterpriseDataTable` from privileges (`flex: 0`, nowrap icons). Do not hard-code `width: 180` in module pages.
+
+## Reload
+
+Toolbar includes search, filter, and reload. Reload calls `gridApi.refreshServerSide({ purge: true })` — never `window.location.reload()`. i18n: `common:actions.reload`.