Decouple common/utils/utils from legacy stores so Storybook can use the real Utils

[talissoncosta]

Background

In #7100 we set up Storybook for component rendering. To keep stories isolated, we had to stub common/utils/utils because the real module triggers a webpack initialisation error in Storybook:

utils → common/stores/account-store → common/constants → … → utils

The circular chain crashes the bundler at module init time.

The current workaround lives in frontend/.storybook/stubs/utils.js — a hand-rolled subset of Utils with simplified implementations of:

• colour
• GUID
• fromParam
• escapeHtml
• getFlagsmithHasFeature / getFlagsmithValue / getPlansPermission
• isSaas
• keys.isEscape
• safeParseEventValue

Problem

Stories render against the stub, not production Utils. Behaviour can drift:

• The stub's GUID is a Math.random() shim, not whatever production uses (uuid?).
• The stub's fromParam does a basic URLSearchParams parse and won't handle nested keys, repeat params, or type coercion the same way production does.
• The stub's colour happens to match production today but won't pick up future changes (dark-mode-aware fallbacks, etc.).
• Any new Utils.* method added to production has to be manually mirrored in the stub or stories using it will break.

This makes Storybook a less reliable visual reference for components that use Utils.

Proposed fix

Break the circular dependency in production so Storybook can import the real common/utils/utils:

1. Identify the cycle. The stub comment points at utils → account-store → constants. Map the full chain and decide which edge to cut.
2. Likely candidates:
   • Move whatever utils.tsx needs from account-store into a small data-only module that doesn't pull constants back in.
   • Or split utils.tsx into a leaf module (no store imports) and a shell that re-exports + adds store-aware helpers — only the shell would be unsafe to import in Storybook, but most stories don't need those helpers.
3. Once the cycle is gone, drop frontend/.storybook/stubs/utils.js and remove the alias from frontend/.storybook/main.js.
4. Verify stories still render and that the legacy .js components depending on Utils (Input.js, etc.) still work in stories.

Acceptance criteria

• frontend/.storybook/stubs/utils.js is deleted.
• frontend/.storybook/main.js no longer aliases common/utils/utils to a stub.
• npm run storybook boots cleanly and all stories render.
• Spot-check stories that use Utils.colour, Utils.GUID, and Utils.fromParam (ToggleChip, Checkbox, Tabs) — same visual behaviour as before.

Notes

• Originating PR: feat: add Storybook stories for pure components #7100
• This is foundation work for the broader "stories as design system source of truth" effort. Until this lands, Storybook documents components against a slightly different runtime than production.