Refactor: Modernize budget viewer state with Signals

[IsaacVic-Dark]

Briefly explain how you went about this assignment and the key benefits of using
Signals over the previous RxJS approach in this UI scenario.

i approached this assignment by getting deep insight on Signals and RxJS. i first replaced constructors with inject(), converted Observables to signal(), used computed(), replaced subscribe() with effect() and used ChangeDetectionStrateg.OnPush in to remove subscription based change.
Some of the benefits is that no subscription is needed, this is beneficial since sometimes developers forget to unsubscribe leading to memory leaks.
signals are synchronous by default, this avoids unnecessary async overhead UI state.

Explain how you understand the difference in coding styles between the two.
for RxJS developer must remember to unsubscribe to prevent memory leaks but for signals, angulars manages the effect lifecycle

Explain how signals and observables works and if there’s a fundamental
difference between the two
signals, updates and values happen immediately, synchronous in nature while in observables, you must subscribe first and operations are handled asychronously

Mention an example of another coding paradighm or style you’ve used in the
past. What is better/worse about that one?
i have used declarative programming in React. for example where i display list of lets say user in UI using map.
advantages of this:
its easy to read and automatically updates the UI
disadvantages of this:
developer does not have much control over how things are updated.