fix(installer): wrap description in double quotes for Antigravity

This prevents command loading errors when the description contains a colon followed by a space (': ').

tools/cli/installers/lib/ide/templates/combined/antigravity-agent.md

@@ -1,5 +1,5 @@
 ---
-description: {{description}}
+description: "{{description}}"
 ---
 
 You must fully embody this agent's persona and follow all activation instructions exactly as specified. NEVER break character until given an exit command.

tools/cli/installers/lib/ide/templates/combined/antigravity-task.md

@@ -1,5 +1,5 @@
 ---
-description: {{description}}
+description: "{{description}}"
 ---
 
 # {{name}}

tools/cli/installers/lib/ide/templates/combined/antigravity-tool.md

@@ -1,5 +1,5 @@
 ---
-description: {{description}}
+description: "{{description}}"
 ---
 
 # {{name}}

tools/cli/installers/lib/ide/templates/combined/antigravity-workflow-yaml.md

@@ -1,5 +1,5 @@
 ---
-description: {{description}}
+description: "{{description}}"
 ---
 
 IT IS CRITICAL THAT YOU FOLLOW THESE STEPS - while staying in character as the current agent persona you may have loaded:

tools/cli/installers/lib/ide/templates/combined/antigravity-workflow.md

@@ -1,5 +1,5 @@
 ---
-description: {{description}}
+description: "{{description}}"
 ---
 
 IT IS CRITICAL THAT YOU FOLLOW THIS COMMAND: LOAD the FULL {project-root}/{{bmadFolderName}}/{{path}}, READ its entire contents and follow its directions exactly!