feat: view tab widget toggle commands and unified SVG icon color scheme

Integrate NAVVCUBE, NAVBAR, PROPERTIES, FILETAB, LAYOUTTAB, TOOLPALETTES
and SHEETSET commands to toggle UI widgets at runtime. Add 15 new SVG icons
for view module tools previously using glyph fallbacks. Restyle all SVG
icons to use the established two-color scheme: #e0e0e0 for passive geometry,
#4cc9f0 for active/accent elements.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/commands.rs

@@ -3706,6 +3706,41 @@ impl H7CAD {
                 }
             }
 
+            // ── NAVVCUBE — toggle ViewCube visibility ────────────────────────────
+            "NAVVCUBE" => {
+                return Task::done(Message::ToggleViewCube);
+            }
+
+            // ── NAVBAR — toggle navigation toolbar visibility ────────────────────
+            "NAVBAR" => {
+                return Task::done(Message::ToggleNavbar);
+            }
+
+            // ── PROPERTIES — toggle Properties panel visibility ──────────────────
+            "PROPERTIES" | "PR" | "PROPS" => {
+                return Task::done(Message::ToggleProperties);
+            }
+
+            // ── FILETAB — toggle file/document tabs ──────────────────────────────
+            "FILETAB" => {
+                return Task::done(Message::ToggleFileTabs);
+            }
+
+            // ── LAYOUTTAB — toggle layout/paper-space tabs ───────────────────────
+            "LAYOUTTAB" => {
+                return Task::done(Message::ToggleLayoutTabs);
+            }
+
+            // ── TOOLPALETTES — not yet implemented ───────────────────────────────
+            "TOOLPALETTES" | "TP" => {
+                self.command_line.push_info("TOOLPALETTES: Tool Palettes not yet implemented.");
+            }
+
+            // ── SHEETSET — not yet implemented ───────────────────────────────────
+            "SHEETSET" | "SSM" => {
+                self.command_line.push_info("SHEETSET: Sheet Set Manager not yet implemented.");
+            }
+
             // ── XDATA — read/write extended entity data ──────────────────────────
             // XDATA LIST             — show all xdata records on selected entities
             // XDATA SET <app> <str>  — append a string xdata value for <app>