[Bug]: Crash when re-enabling "AI" on first column after setting PK on second column #3953

What did you do?

[DB] Browser for SQLite crashes when re-enabling the AI (Auto Increment) checkbox on the first column, after setting PK (Primary Key) on the second column. In this scenario, the AI checkbox is silently disabled (unchecked) on the first column, but PK remains checked on the second.

Steps to Reproduce:

1. Create a new table
2. Add two columns (e.g. id and title)
3. In the first column (id), check AI → Note: PK is auto-checked as well
4. In the second column (title), check PK → The AI in the first column is now silently unchecked (but PK remains in the second column)
5. Now go back to the first column and re-check AI
6. The application crashes immediately without warning or error message.

Crash is 100% reproducible

What did you expect to see?

Either a warning should appear saying AI can only be enabled if that column is the sole primary key or AI should be greyed out / disabled unless PK is active on the same column

What did you see instead?

The application crashes immediately without warning or error message.

DB4S Version

3.13.1

What OS are you seeing the problem on?

MacOS

OS version

Sequoia 15.5

Relevant log output

Process:               DB Browser for SQLite [36691]
Path:                  /Applications/DB Browser for SQLite.app/Contents/MacOS/DB Browser for SQLite
Identifier:            net.sourceforge.sqlitebrowser
Version:               3.13.1 (3.13.1)
OS Version:            macOS 15.5 (24F74)
System Integrity Protection: enabled

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000001
Termination Reason:    SIGNAL 11 Segmentation fault

Crashed Thread:        0  Dispatch queue: com.apple.main-thread
Crash Function:        sqlb::Table::removeKeyFromConstraint(...)

Thread 0 Crashed:
0   DB Browser for SQLite    sqlb::Table::removeKeyFromConstraint(...) + 1123
1   DB Browser for SQLite    EditTableDialog::fieldItemChanged(...) + 6435
2   QtWidgets                QTreeWidgetItem::setData(...) + 1323
...

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