refactor: update documentation structure and guidelines for TrackGo

- Revised the `doc-updater` documentation to clarify the separation between user and technical documentation, specifying locations and audiences for each type.
- Introduced new rules for authoring user documentation in VitePress, emphasizing the exclusion of technical content and the use of PlantUML for diagrams.
- Added a new `documentation.mdc` file to outline the documentation split and rules for maintaining clarity and consistency across the codebase.
- Updated existing documentation to reflect the new guidelines, ensuring a streamlined approach to documentation management.

These changes enhance the clarity and organization of documentation efforts, improving the overall user experience and maintainability of the codebase.

.cursor/rules/user-docs.mdc

@@ -0,0 +1,89 @@
+---
+description: How to write TrackGo user docs in VitePress (apps/docs-dev)
+globs: apps/docs-dev/**
+alwaysApply: false
+---
+
+# User Documentation (VitePress)
+
+Audience: customers and operators. Location: `apps/docs-dev/`.
+
+## Scope
+
+Document **features and usage** (menus, screens, workflows) for:
+
+- Web — `apps/web`
+- Mobile — sibling `trackgo_mobile`
+
+Do **not** document tech stack, package internals, Electron IPC, or monorepo setup here. Technical docs belong in `trackgo-be/docs/` (MkDocs).
+
+## Where to add pages
+
+Prefer:
+
+```text
+apps/docs-dev/src/user/web/
+apps/docs-dev/src/user/mobile/
+```
+
+Register new pages in `src/.vitepress/config.mts` sidebar/nav.
+
+Do **not** add new pages under the legacy architecture sidebar paths (`/packages/*`, `/apps/desktop/*`, `/setup`, `/overview`). Those stay until a later migration; do not expand them.
+
+Existing user how-tos (e.g. `src/apps/web/SALES_WORKFLOW.md`): keep user-facing; when editing, convert Mermaid to PlantUML and remove emoji.
+
+## Topics (only if present in code)
+
+**Web** (from menus / modules — verify in `apps/web`):
+
+- Master data: company settings, branches, divisions, customers, products, employees
+- Users and privileges
+- Plans (one-time / recurring) and attached invoices / packing slips
+- Live timeline / activity history
+- Import of invoices / packing slips
+- Sales flow: request → order → invoice → payment
+- Logistics packing slips
+
+**Mobile** (from `trackgo_mobile/lib/ui/features/` and `lib/config/router.dart`):
+
+- Branch check-in before work
+- Plans, customers / visits, invoice payment
+- Home performance / history
+
+Anything in a product brief that is not in the code → **Coming soon**.
+
+## Style
+
+- No emoji.
+- Diagrams / sequences: PlantUML only (do not add Mermaid on new or edited pages).
+- Icons: `lucide-vue-next` in markdown `<script setup>`, same Lucide names as web menus.
+
+````markdown
+```plantuml
+@startuml
+actor User
+User -> Web: Create sales order
+@enduml
+```
+````
+
+```vue
+<script setup>
+import { ShoppingCart } from 'lucide-vue-next'
+</script>
+```
+
+```text
+# BAD — new architecture page in docs-dev
+apps/docs-dev/src/packages/core-api/new-api.md
+
+# BAD — Mermaid / emoji / React Lucide in VitePress
+```mermaid
+```
+"📦 Sales"
+import { ShoppingCart } from 'lucide-react'
+
+# GOOD
+apps/docs-dev/src/user/web/sales-workflow.md
+apps/docs-dev/src/user/mobile/check-in.md
+```