feat: Auto-name clusters and allow renaming them

[Harsh16gupta]

Instead of showing "Cluster 1", "Cluster 2", etc., clusters now get real names based on what's actually inside them.

How it works:

• Picks the most descriptive keywords from each cluster using TF-IDF (looks at unigrams, bigrams, and trigrams)
• Maps them to clean category names like "Travel", "Recipes", "Investment" when there's a clear match
• Falls back to the top-scoring phrase when no category fits
• Handles name collisions — if two clusters both want "Recipes", they get disambiguated

Renaming:

• Click the pencil icon next to any cluster name to rename it
• Press Enter to save, Escape to cancel
• Works in both light and dark themes

Screenshot:

[Harsh16gupta]

Auto-naming the clusters took a few tries to get right:

• At first, the names looked weird and had trailing filler words (like "Meal Prep & Tracking Macro Crazy").
• I fixed that by splitting sentences by newlines and stripping out adverbs. That helped, but some folder names were still too wordy.
• So I mapped them to clean folder names (like "Travel" or "Investment"). I also added a safety net so if two folders got the same name, it adds a subtopic (like "Recipes (Flour)" vs "Recipes (Meal Prep)").
• Lastly, I added a pencil edit button in the UI so you can manually rename folders if you don't like what the algorithm picked!

[HahaBill]

Hi! Thank you for this PR, before reviewing there are some merge conflicts. Let me know when you resolve all the conflicts 👍

[HahaBill]

Looking at this PR, I think for releasing the first version for getting feedback from the community is good enough.

There are couple of issues that I can see but we can address them after the midterm evaluation since the plan was to focus on releasing the the first version of this plugin before/during the midterm evaluation. Also, we are ahead of the schedule that you wrote in your proposal :)

Since this version of the plugin is still under the development and unoptimal, then I'd suggest semantically version this as 0.1.0. Look this link explaning what is semantic versioning: https://semver.org/. Then you release small patches from user feedback with smart versioning like 0.1.1.

After resolving conflicts, this can be merged to the main branch.

[Harsh16gupta]

Thanks for the review!

Regarding the first release, I think I'll need about one more week. There are a few basic things I'd like to finish first. For example, the plugin currently shows the suggested changes, but there's no way for users to apply them yet. I also want to clean up the UI and make a few minor improvements here and there.

I think it would be better to release v0.1.0 next week after these are done, rather than shipping with these rough edges.

Also, the Joplin API we're relying on hasn't been released to users yet, so I think waiting another week makes sense.
wdyt?

[HahaBill]

Thanks for the review!

Regarding the first release, I think I'll need about one more week. There are a few basic things I'd like to finish first. For example, the plugin currently shows the suggested changes, but there's no way for users to apply them yet. I also want to clean up the UI and make a few minor improvements here and there.

I think it would be better to release v0.1.0 next week after these are done, rather than shipping with these rough edges.

Also, the Joplin API we're relying on hasn't been released to users yet, so I think waiting another week makes sense. wdyt?

Alright, let's discuss this during our weekly call.

In a meantime, I'm merging this into the main branch.