chore: Implement skill

[ppraneth]

Adds skills\implement-method

[ValerianRey]

I think this is very good, tyvm!

A few notes:

• Could you test this skill on a method you've recently implemented? Basically, revert the commit in which you implemented the method, then use the skill to implement it (the row will be missing from the tracker so you'll have to call the research skill too), and see if the proposed implementation by the agent is good enough to serve as a base. If you see problems that can be easily fixed by changing the skill, do that. We don't need the result to be perfect, or to be identical to the implementation that we ended up merging, but we should fix obvious flaws if any.
• Need an equivalent reference but for aggregators (+ a few examples in step 4 of the skill). @KhusPatel4450, would you be interested in adding that? Otherwise I can try
• I don't think we'll need a review skill. But I think we should add a code review step after the verify step, just asking the agent to check that everything was respected in the code it produced, and to improve what can be improved.

[ppraneth]

@ValerianRey I also tested the skills, and they work good.