…#3324)

### Motivation

Resolves #3321

The ripple effect in Paywalls V2 ignores rounded corners and extends
into the component's margin area. This happens because
`Modifier.clickable()` is applied before `StackComponentView` applies
`.clip(shape)` and margin internally — so the ripple fills the entire
rectangular area including margins.

### Description

Introduces an `interactionModifier` parameter on `StackComponentView`
that gets threaded down to `MainStackComponent` and applied **after**
`.clip(composeShape)` in all 4 code paths (standard, video background,
nested badge, overlay). This ensures the ripple is bounded by the
component's actual shape.

Updated all callers:
- **ButtonComponentView** — moves `clickable` into `interactionModifier`
- **PackageComponentView** — moves conditional `clickable` into
`interactionModifier`, removes unused `conditional` import
- **TabControlButtonView** — moves `clickable` into
`interactionModifier`

Also adds a `ButtonComponent` to the bless sample paywall (#8) to make
it easier to reproduce and verify the fix visually.

**Testing:** All existing unit tests pass — StackComponentViewTests,
StackComponentViewWindowTests, ButtonComponentViewTests,
PackageComponentViewTests, TabsComponentViewTests. Verified visually via
the updated sample paywall.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Touches the core `StackComponentView` container and changes where
click/interaction modifiers are applied, which could subtly affect touch
targets and interaction behavior across multiple paywall components.
Functionality is UI-scoped (ripple/press feedback) with no data/auth
implications.
> 
> **Overview**
> Fixes Compose ripple/press feedback on paywall components so it
respects rounded corners and does not extend into margins by adding an
`interactionModifier` to `StackComponentView` and applying it **after**
`clip(shape)` across all rendering paths (standard, video background,
nested badge, overlay/badge variants).
> 
> Updates callers (`ButtonComponentView`, `PackageComponentView`,
`TabControlButtonView`) to pass their `Modifier.clickable` via
`interactionModifier` (instead of on the outer `modifier`), and tweaks
the paywall tester sample (#8) to use a `ButtonComponent` to make the
issue easy to reproduce/verify.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
c7368b0. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

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Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>