[FEAT]: Add relation field drop-down list with linked filtered records navigation

[youssef-elmelegy]

Add support for relation fields that allow users to view and navigate to related records from parent tables.

Features

• Display relation fields as interactive dropdowns
• Show list of related records from the linked table
• Provide "Open in table" action to navigate to filtered view
• Auto-apply filter using parent record's ID

Example: Chat Messages Relation

Clicking messages relation field in chats table:

1. Dropdown shows all messages belonging to that chat
2. "Open in table" button available
3. Opens messages table with filter: chatId = '5a3f2b...'

Detailed Flow

chats table (parent)
└── messages relation field
    ├── Shows: "Hello there!", "How are you?", "See you soon!"
    └── Click "Open in table" 
        → Opens messages table
        → Filter applied: WHERE chatId = '5a3f2b1c-4d5e-6f7g-8h9i...'

Flow Diagram

┌─────────────────────────────────┐
│   chats Table                   │
│  ┌─────────────────┬──────────┐ │
│  │ Chat Name       │ messages │ │
│  ├─────────────────┼──────────┤ │
│  │ Team Discussion │    ▼     │◄┼─── Click relation field
│  └─────────────────┴──────────┘ │
└──────────────┬──────────────────┘
               │
               ▼
┌───────────────────────────────────────┐
│  Dropdown Menu (Preview)              │
│  ┌─────────────────────────────────┐  │
│  │ • "Hello there!" - Alice        │  │
│  │ • "How are you?" - Bob          │  │
│  │ • "See you soon!" - Charlie     │  │
│  │ • "Thanks everyone" - Alice     │  │
│  │                                 │  │
│  │      (147 messages total)       │  │
│  ├─────────────────────────────────┤  │
│  │   [📖 Open in table] ──────────►│  │
│  └─────────────────────────────────┘  │
└───────────────────────────────────────┘
               │
               ▼
┌──────────────────────────────────────────────────┐
│   messages Table (Filtered)                      │
│   WHERE chatId = '5a3f2b1c-4d5e-6f7g...'         │
│   Active Filter: chatId equals "Team Discussion" │
│  ┌────┬─────────────────┬────────┬──────────┐    │
│  │ id │ content         │ sender │ created  │    │
│  ├────┼─────────────────┼────────┼──────────┤    │
│  │ 1  │ Hello there!    │ Alice  │ 10:23 AM │    │
│  │ 2  │ How are you?    │ Bob    │ 10:25 AM │    │
│  │ 3  │ See you soon!   │ Charlie│ 10:30 AM │    │
│  │ 4  │ Thanks everyone │ Alice  │ 10:32 AM │    │
│  └────┴─────────────────┴────────┴──────────┘    │
└──────────────────────────────────────────────────┘

Nested Relations Example

users table
└── chats relation (user's chats)
    └── messages relation (chat's messages)
        └── attachments relation (message's files)

Navigation path:
users → filter chats by userId 
      → filter messages by chatId 
      → filter attachments by messageId

Acceptance Criteria

• Relation fields render as interactive dropdowns
• Dropdown shows preview of related records (e.g., first few messages)
• Display record count in dropdown (e.g., "147 messages total")
• "Open in table" action navigates to related table
• Automatic filter applied using parent record ID
• Filter is visible and editable in target table
• Support for nested relations (e.g., user → chats → messages → attachments)
• Handle empty relations gracefully (show "No messages" state)

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