сhore(agtree): add node-specific clone utility

[SatoruFF]

Closes? #153

The converters were using clone-deep to copy rule nodes before mutating them.
Since we know the exact shape of every node type, a generic deep-clone is overkill —
so this adds node-specific clone functions instead.

What's added

• cloneAnyRule — main entry point, dispatches by node.category
• cloneAnyCommentRule, cloneAnyNetworkRule, cloneAnyCosmeticRule — typed generics
  so the specific subtype is preserved at call sites
• Existing helpers (cloneScriptletRuleNode etc.) are untouched

What's changed

Replaced clone(rule) + TODO comments in three converter files with the new functions.

Tests

test/ast-utils/clone.test.ts — covers all rule categories, checks both value equality
and that no object references are shared between original and clone.

[scripthunter7]

Thanks for putting together this PR, but I think it's a bit too early to merge it. There is already a task for this in AGTree v5 (which you also linked), and we're planning to implement it at the appropriate stage.

It's important to note that v5 will also modify and improve the node types to some extent, and we’re not planning to add this kind of feature to v4 anymore.

[scripthunter7]

I wrote a small benchmark script that showed it's more efficient to list properties explicitly rather than using the spread operator, enumerating properties is about 1.5x faster, but depends on the platform. If we want to avoid generic solutions anyway, it's a better idea to go with that approach.

[scripthunter7]

Instead of using map, it's more efficient to preallocate an array of the same length and fill it using a simple for loop without any spread operator.

[scripthunter7]

Generally, we should avoid using structuredClone where possible, as it is quite slow, although this can be platform-dependent. It's interesting by the way, because at first you wouldn't expect this, since it's a native implementation, but even clone-deep can outperform it :)