Add automation breadcrumbs and pane full-screen controls

[brsbl]

Adds the next focused layer on top of #941.

Changes:

• Reuses the Extensions breadcrumb renderer for Automations installed, browse, detail, edit, loading, and missing-data routes.
• Makes pane Full Screen the immediate click action and exposes supported split move actions on hover.
• Uses Exit Full Screen for the maximized-state tooltip and restores the plain X for thread-pane close.
• Adds focused route, interaction, split-wiring, and Ladle coverage.

Verification:

• 54 focused app tests passed.
• pnpm exec turbo run typecheck --filter=@bb/app passed on Node 22.22.1.
• BB desktop app verified Automations Installed and Browse breadcrumbs and navigation.

Stack parent: #941.

[brsbl]

Final stack update:

• Applied the right-sidebar/thread UI patch without unrelated plugin/workflow changes.
• Added automation breadcrumbs and the pane Full Screen / arrangement interaction.
• Restored a plain X for both thread and plugin pane close controls.
• Unified maximize and close controls on one centered pane-header geometry, verified in the BB desktop app.
• Regenerated the shared icon registry and plugin starter template.
• Fixed the breadcrumb effect dependency reported by CI lint.

Verification:

• Focused pane/header suite: 45 tests passed on this layer.
• Full combined package matrix from the top stack: 11 Turbo tasks passed; @bb/app 2,339 tests; @bb/templates 14 tests; relevant app/automations/shared-ui/plugin-registry/templates typechecks passed.
• BB app QA covered automation breadcrumbs/detail states, plain-X close controls, aligned header actions, full-screen entry/exit, arrangement menu, and no collapsed rail while maximized.
• No unresolved review threads.

Not merged.