Rename theme to 'Socratic Shell: Code Review'

**Branding Update: Align with Socratic Shell identity**

**Changes:**
- Sidebar title: 'Dialectic' → 'Socratic Shell'
- View name: 'Pull Request' → 'Code Review'

**Result:** Extension now displays as 'Socratic Shell: Code Review' in VSCode sidebar, better reflecting the collaborative philosophy and broader scope beyond just pull requests.

Author: nikomatsakis

extension/package.json

@@ -63,7 +63,7 @@
       "activitybar": [
         {
           "id": "dialectic",
-          "title": "Dialectic",
+          "title": "Socratic Shell",
           "icon": "logo.svg"
         }
       ]
@@ -72,7 +72,7 @@
       "dialectic": [
         {
           "id": "dialectic.syntheticPR",
-          "name": "Pull Request"
+          "name": "Code Review"
         }
       ]
     },