feat: implement project selector dropdown and inline new project creation

[Vasist10]

Description

This PR implements a project selection dropdown with an inline “Create New Project” option within the tasks view.
It allows users to select an existing project or quickly create a new one without navigating away.

• Updated the Project field in Add Task: replaced free-text input with a Select dropdown.
• Added isCreatingNewProject UI state to allow switching between selecting an existing project and creating a new one inline.
• Included “+ Create new project…” option in the dropdown, which reveals an input for entering a new project name.
• Compute uniqueProjects from IndexedDB tasks (deduplicated & alphabetically sorted).
• On manual sync, recompute project list from synced tasks so the dropdown reflects latest data.

Added two new tests in Tasks.test.tsx:

• lists existing projects + create-new option

• reveals input when selecting Create-new option

• All existing tests continue to pass

• Fixes: Add Project Dropdown With Inline “Create New Project” Option #204

Checklist

• Ran npx prettier --write . (for formatting)
• Ran gofmt -w . (for Go backend)
• Ran npm test (for JS/TS testing)
• Added unit tests, if applicable
• Verified all tests pass
• Updated documentation, if needed

Additional Notes

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[its-me-abhishek]

Please add a self review and tests for this PR

[Vasist10]

Please add a self review and tests for this PR

@its-me-abhishek
I’ve added the tests and updated the PR.
Let me know if anything else is needed.

[its-me-abhishek]

this can be improved i guess, __create__ seems to be an arbitrary value/variable

[its-me-abhishek]

needs to be replaced with something similar to what we use in other constants, maybe an isCreate flag, or just an empty text, whatever works

[Vasist10]

@its-me-abhishek I have replaced value constant with isCreatingNewProject flag.

[its-me-abhishek]

Merged! Thanks for the PR!