* Let anyone with a strategy link view it without an account

A signed-out person who opened a share link was told to sign in and saw
nothing. Now a strategy link opens that strategy read-only for anyone
holding it, account or not.

The server's strategy, page, and image reads take an optional shareToken:
a live link to that strategy grants viewer access, never a write, and
stops working when its owner disables it. shares:resolve tells a client
what a link opens. No caller without a token changes, so the live web
build and shipped desktop builds keep working.

On the client, a signed-out reader goes straight to the strategy. The
toolbar's save button becomes a sign-in button, and signing in redeems
the link into their Shared library as before. A disabled link closes the
strategy and says so. Folder links still need an account.

A view-only strategy also drops the Tools/Agents sidebar and the trash
zone, none of which respond for a viewer; the map takes their width.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

* Keep link views honest after sign-in, on desktop, and in the dialog

A signed-out lookup that finished after sign-in had redeemed its link
could reopen the link view; an attempt now drops when its code is no
longer held. Redeeming the link of the open strategy now records it for
reload. A desktop image refresh carries the link a signed-out reader
opened. And the share dialog promises a view without an account only
where links open in a browser: desktop links hand off to the app.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

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Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>