Project tabs use canonical paths #239

Overview and Settings no longer use query-string tabs; project navigation now uses explicit /overview, /memories, /tasks, /moderation, and /settings paths.

The unreliable ?tab=overview workaround was removed together with the remaining query-tab parsing and legacy ?tab=reviews redirect. HTTP rendering verifies active Overview and Settings links. The changes were included in parallel commit 65e7c86; all 87 tests passed. Not deployed yet.