fix(fast-html): bind event handlers to correct host inside f-repeat

[mohamedmansour]

Summary

Event handlers inside <f-repeat> now have their this context correctly bound to the host element instead of the repeat item.

Changes

• utilities.ts: Extracted shared path-building logic from pathResolver into buildResolvedPath helper. Added eventOwnerResolver that resolves the owner of a method by walking the same context chain but stopping one segment before the method name (e.g. c.parent at nesting level 1).
• template.ts: Changed .bind(x) to .bind(ownerResolver(x, c)) in the @ event binding branch, using eventOwnerResolver to determine the correct this target.

What still works

• Level 0 (no repeat): eventOwnerResolver returns x (the host itself), so behavior is identical to before.
• Self-referencing paths: Paths like item.doSomething that start with the repeat context variable correctly resolve the owner to the repeat item (x), not the host.
• Nested repeats: The context-walking logic respects nesting depth, traversing parentContext/parent chains as needed.
• All existing tests pass (365 Chromium + WebKit tests).

Fixes #7329.

[radium-v]

In a repeat directive, the template (second arg) expressions are bound to the result of the data binding result (first arg):

type Item = string;
type Items = Item[];

class MyElement extends FASTElement {
    public items: Items = ["one", "two", "three"];

    public someValue: string = "some value";

    public itemClickHandler(event: Event) {
        console.log("item clicked", event);
    }
}

export const template = html<MyElement>`
    ${repeat(
        x => x.items, // <-- the data binding object (aka `x` for bindings within the repeat's template)
        html<Item, MyElement>`
            <!-- the template data binding is `Item`, the template binding context is `MyElement` -->
            <button
                @click="${(currentItem: Item, thisBindingContext) =>
                    thisBindingContext.parent.itemClickHandler(thisBindingContext.event)}"
            >
                ${
                    // bindingContext allows access to the parent in any binding, anywhere in template expressions
                    (currentItem, bindingContext) => bindingContext.parent.someValue
                }
            </button>
        `
    )}
`;

In FAST HTML, we need to add a way to access the template binding context from within the repeat template, instead of re-contextualizing all bindings within an f-repeat. Providing access to the context object in any binding expression in declarative templates would be the right way to approach this problem.