Document (#6)

* docs: add flutter-architecture.md

* docs: add guildlines/conventional-commit.md

* docs: add database-schema.md

* add readme.md

* chore: fix misspelled folder name

Author: tqha1011

documentation/guidelines/conventional-commit.md

@@ -0,0 +1,24 @@
+## 📌 Git Commit Convention
+
+To maintain a clean, readable, and trackable commit history, all team members **MUST** adhere to the following commit guidelines.
+
+### 1. Standard Syntax
+`<type>(<scope>): <short_description>`
+
+### 2. Allowed Types
+
+| Icon | Type | Description | Example |
+| :---: | :--- | :--- | :--- |
+| ✨ | **feat** | Adds a new feature to the application. | `feat(auth): add JWT login API` |
+| 🐛 | **fix** | Patches a bug or resolves an issue. | `fix(cart): resolve incorrect total price calculation` |
+| ♻️ | **refactor**| Restructures code without changing existing logic or adding features. | `refactor(product): clean up IProductService interface` |
+| 📝 | **docs** | Adds or updates documentation (README, diagrams, etc.). | `docs(ci): update SonarCloud workflow` |
+| 🔧 | **chore** | Maintenance tasks, configurations, or dependency updates. | `chore(deps): bump Newtonsoft.Json to 10.0.4` |
+| 🚀 | **perf** | Code changes that improve performance. | `perf(db): add index to Product table for faster queries` |
+
+### 3. Golden Rules
+- The `type` and `scope` MUST strictly be in **lowercase**.
+- The description must be clear, concise, and straight to the point.
+- **NEVER** push code with meaningless commit messages such as: `update`, `fix bug`, `done part A`, `asdfgh`.
+
+Reference: [Conventional Commit](https://www.conventionalcommits.org/en/v1.0.0/)