fix: Address workspaces review results

[milosh86]

Description

Follow-up fixes from the workspaces review.

• Feature flag gating: LayoutWorkspace, LayoutWorkspaceAccount and LayoutWizardCreateWorkspace now check the workspaces flag and return notFound(). Before this, only the pages were gated, so with the flag off the layouts still rendered the workspace navigation, the gate and the wizard around the 404, and still prefetched from the backend. Docs in createWorkspace.md updated.
• useWorkspaceDaos cache corruption: the hook used to mutate the DAO object from the shared daoOptions cache when applying the workspace account metadata (name, avatar, description), so the overrides leaked into the rest of the app. It now builds a copy. It also looks up the account by the query's id instead of dao.id.
• Proposals page: the "New proposal" action is hidden until the workspace DAOs have loaded.
• Publish workspace dialog: exported through next/dynamic, like the other dialogs.

Type of Change

• Patch: Bug fix (non-breaking change which fixes an issue)

Developer Checklist:

• Manually smoke tested the functionality in a preview or locally
• Confirmed there are no new warnings or errors in the browser console
• (For User Stories only) Double-checked that all Acceptance Criteria are satisfied
• Confirmed there are no new warnings on automated tests
• Merged and published any dependent changes in downstream modules
• Selected the correct base branch
• Commented the code in hard-to-understand areas
• Followed the code style guidelines of this project
• Reviewed that the Files Changed in Github’s UI reflect my intended changes
• Confirmed the pipeline checks are not failing

Review Checklist:

• (For User Stories only) Tested in a preview or locally that all Acceptance Criteria are satisfied
• Confirmed that changes follow the code style guidelines of this project

[github-actions]

🚀 Preview Deployment: View Here

[github-actions]

E2E results (preview)

Smoke

Base URL	https://app-next-63j291k8a-aragon-app.vercel.app
Suite	smoke
Playwright result	✅ passed
Summary	86 passed
HTML report	View report
GitHub job	✅ completed

View run #5512

[thekidnamedkd]

Could we keep accounts without a resolved DAO out of this flow, the way the transactions page does? A rejected DAO query clears isDaosPending, so the button reappears and picking that account dead-ends in an empty process dialog.