[IMP] rename "Issue" to "Task"; remove "Create Date" column

[gjotten]

• Replace all visible references to "issue" with "task" in the popup UI (column headers, alert messages, button titles). The dataSource variable is already project.task-aware but many strings use "issue" unconditionally (e.g. popup-app.js:1163, 1199, 1217)
• Remove the "Create Date" table column; it is low-value and contributes to width overflow