Sidebar: group nav into priority-ordered functional sections

Turn the flat sidebar into a data-driven nav: each entry declares a
group (workspace/extensions/config/dev) and a numeric priority, and each
section renders by sorting on that key. Split axis is function, not
permission — adminOnly/debugOnly gate individual entries and an empty
section is hidden, so Configuration vanishes for non-admins without a
section-level role check.

- Shared folders moves into 'Your space' (still admin-gated per-entry).
- Plugin pages merge into the workspace group on the same priority line
  (>=100 by default); rebase the two in-repo plugins accordingly.
- Configuration and Development are collapsible, closed by default,
  state persisted in localStorage. Simple mode unchanged.
- Rename nav.catalog to 'Connectors Catalog' to disambiguate from the
  Plugin Catalog; add nav.section.* header keys (en/it/fr).
- Replace dead .sidebar-section-toggle CSS with real section classes.

crates/plugin-honcho/src/lib.rs

@@ -863,7 +863,9 @@ impl core_api::plugin::Plugin for HonchoPlugin {
                 icon:       "gear",
                 entry:      "web/config.js".into(),
                 admin_only: true,
-                priority:   10,
+                // Sidebar priority: core "Your space" items live in 10–90, so
+                // plugin pages use ≥100 to land after them (see sidebar.js NAV).
+                priority:   120,
             },
             PluginPage {
                 page_id:    "memory",
@@ -871,7 +873,7 @@ impl core_api::plugin::Plugin for HonchoPlugin {
                 icon:       "stars",
                 entry:      "web/memory.js".into(),
                 admin_only: false,
-                priority:   10,
+                priority:   130,
             },
         ]
     }