Improve import dialog with column sorting and better visibility

[SougandhS]

Improves the import dialog usability by adding column-based sorting for the “Folder” and “Import As” columns (with ascending/descending toggle on header click) and increasing the proposals list height to display more entries by default. This aligns sorting with the displayed column values and makes it easier to scan and organize import proposals, especially when dealing with many entries, reducing the need for manual resizing.

Video.mp4

[github-actions]

Test Results

   852 files  ±0     852 suites  ±0   58m 23s ⏱️ + 9m 3s
 7 913 tests ±0   7 670 ✅ ±0  243 💤 ±0  0 ❌ ±0 
20 241 runs  ±0  19 586 ✅ ±0  655 💤 ±0  0 ❌ ±0 

Results for commit d5ac23e. ± Comparison against base commit d0eb817.

♻️ This comment has been updated with latest results.

[vogella]

Nice improvement, thanks for working on this. Two small things worth addressing before merge:

1. Clicking the already sorted "Folder" column flips the direction on the very first click, because the comparator is initialized with column = 0 and then setColumn(0) treats it as a repeat click. Users usually expect the first click
   to sort ascending. Consider starting the comparator in an "unset" state (for example column = -1) so the first click lands on ascending.

2. ImportsComparator can be private static. It does not capture any state from SmartImportRootWizardPage (the label provider is passed in via the constructor), so there is no need for the implicit outer reference.

[SougandhS]

Nice improvement, thanks for working on this.

Thanks !

Two small things worth addressing before merge:

Done 👍

[vogella]

New observations:

1. Default-sort regression — column = -1 means the comparator returns 0 on open, so the tree is unsorted while the Folder column still shows a sort indicator (because setSortColumn(folderCol) runs unconditionally during setup).
2. heightHint = 190 — more than 2× the previous value; worth verifying on minimum screen size.
3. NPE risk — projectLP.getText(f1) in case 1 isn't null-guarded.

[SougandhS]

1. Default-sort regression — column = -1 means the comparator returns 0 on open, so the tree is unsorted while the Folder column still shows a sort indicator (because setSortColumn(folderCol) runs unconditionally during setup).

Made few tweaks - Fixed 👍

2. heightHint = 190 — more than 2× the previous value; worth verifying on minimum screen size.

Adjusted it to 150 - I hope its good. with 90 I can see only 4 or 5 items by default.

3. NPE risk — projectLP.getText(f1) in case 1 isn't null-guarded.

Added a guard

[SougandhS]

Thank you @vogella for the review and merging 😊