Sidebar counts, All Memories, Memory promotion, and a sidebar footer that does more

The sidebar now earns its keep. Each Shared Space shows a live Memory count and an Owner shield when you own it, and Spaces you've archived collapse into an "Archived" disclosure at the bottom of the list instead of disappearing. A new All Memories item sits above your Shared Spaces — it opens a single feed of every Memory you can read across your Personal Space and all your Shared Spaces, newest first, with the same Type filter used elsewhere and a scope marker on each card. And any Memory you own can now be moved: the Memory detail page gains a Space control that promotes a private Memory to a Shared Space (so your team and their agents can build on it), moves it between Spaces, or pulls it back to your Personal Space. The sidebar footer also grows two new affordances: a prominent New Memory button that drops you straight into your Personal Space composer, and a What's new item that opens this changelog inside the app.