[Proxicon]

Closes #457

Operator workspace

• Replace the stacked full-width header and policy wall with a bounded-width, responsive two-column overview. Tenant/channel/pin remain visible; explanatory rollout guidance is available in a collapsed Policy details disclosure.
• Bring the tab bar and catalogue higher in the initial viewport; make the release automation summary a compact strip while retaining its guarded settings drawer and error/unsaved states.
• Promote Local imports to a first-class lazy tab instead of placing it below the entire GitHub catalogue. Include search, paging, progress/errors, source check, retry/cancel, protected deletion and cleanup receipts. Refresh continues on the import tab.

Pagination

• Standardize GitHub releases, Local imports, Packages, Auto-updates, Activity and Suspended to 20 / 50 / 100 rows, defaulting to 20.
• Add validated pageSize support end-to-end for the GitHub catalogue, using the existing bounded metadata cache. Preserve the old 20-row API overloads and automation behavior.
• Reset catalogue pagination when page size/channel changes and fence stale requests. Filter and clamp local-import pages without changing the selected catalogue channel.

Regression coverage

• Component tests check actual rendered catalogue/local-import row counts, reset behavior, retained channel, local-data accessibility when upstream fails, and propagation of page size to all four server-backed management tabs.
• Adapt existing release-deletion tests to operate through Local imports, retaining confirmation/blocker/navigation/cleanup assertions.
• Catalogue tests check 20/50/100 slicing, no gaps/duplicates, filtering before paging, cache reuse and backwards-compatible defaults.

Existing tab indices and activity lifecycle, tenant authorization, release verification, publication rules and deletion protections are preserved.

Validation and scope

Use the existing required GitHub-hosted PR validation. Results will be recorded here after execution.

Merge to main only. No product version bump, release tag, release artifacts, container publication or production deployment. Visual deployment acceptance is separate from component/CI verification.