Project side pane: General tab polish

Noticed while verifying Task 7218 (local stack, /projects/1 open in the side pane beside the Directory list, 1024px and 1366px windows). 1. The Cancel/Save bar at the foot of the General tab renders with ~40px of empty dark space below the buttons on current develop; it was one button-height tall before. Keep it as tall as its buttons. 2. In the pane at a 1024px window only General and Access fit in the tab strip, so Governance and Slots go behind More; consider shorter tab gutters so the four most-used tabs stay visible. Out of scope: the Repositories table (Tasks 7207, 7218) and the phone layout (Task 7197). Done means: - At 1024px and 1366px windows with the project open beside the list, each item above is checked visually and screenshotted.

Narrow fitted tab strips use 6px sides, so the 1024px project pane shows General/Access/Governance/Slots before More. The Save bar strip was already fixed by Task 7306; the e2e pins both. Quick gate passed, e2e 7/7, visual check done. PR #5971 queued. Draft follow-up #7382.