Make Overview the default workspace home

[tonyfresher]

Adds Overview as the default workspace home, with a built-in Views launcher and the existing widgets collected under one host-owned surface. It also brings workspace identity editing, styling, settings, hidden widgets, and creation actions into the Overview flow while preserving the proven react-grid-layout movement behavior.

Workspace
├── Overview (default)
│   ├── Views · open or create full-page tools
│   └── Widgets · inspect, hide, restore, or create widgets
├── Agent
└── Scratchpad

The custom dnd-kit canvas is deliberately excluded and remains isolated on the follow-up canvas branch.

Review closely

• Tab normalization pins Overview and removes the retired Widgets route while preserving valid saved tabs.
• New workspaces receive the host-owned Views widget; existing empty or hidden layouts stay unchanged.
• Workspace icon updates rasterize generated choices and serialize rapid actions before persistence.

Verification

• bun test — 1,465 passed, 4 skipped
• bun run typecheck:client
• bun run lint
• bun run format:check
• bun run build:client
• git diff --check
• Browser-tested Overview routing, empty states, Style, settings, icon editing, launchers, and retained RGL rendering.

[molefrog]

Fixed some critical backend issues and pushed. Other minor things for you @tonyfresher

Might need to prevent user select here:

prob an edge case, but would it make sense to remove the text here and make buttons slightly leaner on smaller viewports?

Some other UX things we have discussed already for later PRs:

• Deleting and renaming views is hard to discover, I would expect it to be somewhere when the view is active or in the tab bar
• Moving theme switcher to the Overview feels like a regression, there are cases when one would want to try different themes on other tabs as well
• This is very opinionated, but IMO the title "Views" here is a bit confusing for someone who is not familiar with moi's applet system and takes too much attention. I would maybe iterate a little bit more on that.