Feature: Normalize GovernancePage data shell (EPIC-3.6)

[masvelio]

Summary

Tighten GovernancePage ownership by normalizing its init/data shell without turning the work into a broad over-abstraction exercise.

Problem / Motivation

GovernancePage.tsx is comparatively small, but it still sits in the legacy views tree and owns initialization/data orchestration that should be cleaner before EPIC-4 governance migration. The plan explicitly calls out that the goal here is boundary cleanup, not a large redesign.

Proposed Solution

• Normalize the Governance page entry shell and data/init wiring.
• Extract only the seams needed to separate page orchestration from governance-specific rendering modules.
• Keep the scope narrow and avoid introducing unnecessary abstraction layers.
• Preserve current loading, empty-state, and proposal-navigation behavior.

Acceptance Criteria

• GovernancePage has a clearer separation between page shell and governance-specific rendering/data concerns.
• No unnecessary abstraction or speculative architecture is added.
• Existing governance route behavior is preserved.
• The page structure is ready for EPIC-4.12 migration work.
• Build/typecheck and relevant route/component checks pass.

Alternatives Considered

• Leave GovernancePage untouched until EPIC-4.12. This was rejected because small boundary cleanup now reduces later migration risk.
• Fully redesign the governance page structure. This was rejected because the plan only needs targeted normalization at this stage.

Impact

This is a smaller EPIC-3 task, but it removes low-signal legacy page ownership ahead of the governance feature migration.

Links

• Plan doc: common_knowledge/Commonwealth-Frontend-Refactor-Plan.md
• Milestone: https://github.com/hicommonwealth/commonwealth/milestone/136?closed=1

Additional Context

The plan notes that this should stay intentionally scoped. Treat this as a boundary-cleanup issue, not a wide governance rewrite.