fix: correct concept count and align quiz-bank keys with concept-tree

Audited actual concept count in concept-tree.json — found 39 concepts,
not the claimed 42. Added 3 missing concepts (typescript, testing, python)
that existed in the quiz-bank but had no concept-tree entries. Renamed
quiz-bank keys 'javascript'→'js-basics' and merged 'react' into
'react-components' to match concept-tree IDs exactly.

- total_concepts: 42 in concept-tree.json is now accurate
- All 17 quiz-bank keys now match concept-tree concept IDs
- Black Belt threshold (28/42 = 67%) remains in the 60-70% target range
- README category listings updated to reflect new concepts

Closes DOJ-2432

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

Author: dbejarano820

README.md

@@ -182,12 +182,12 @@ code-sensei/
 
 CodeSensei covers **42 concepts** across **9 categories**:
 
-- **🧱 Fundamentals** — Variables, functions, loops, conditionals
+- **🧱 Fundamentals** — Variables, functions, loops, conditionals, Python
 - **🌐 Web Basics** — HTML, CSS, how browsers work
-- **⚡ JavaScript** — Core JS, async/await, imports, JSON
+- **⚡ JavaScript** — Core JS, async/await, imports, JSON, TypeScript
 - **💻 Terminal & Tools** — Command line, npm, git, env variables
 - **🎨 Frontend** — React, components, props, state, routing
-- **⚙️ Backend** — Servers, routes, middleware, REST APIs, auth
+- **⚙️ Backend** — Servers, routes, middleware, REST APIs, auth, testing
 - **🗄️ Databases** — SQL, schemas, ORMs, relationships
 - **🚀 Deployment** — Hosting, Docker, CI/CD
 - **🏗️ Architecture** — Design patterns, scalability, client-server

data/concept-tree.json

@@ -55,6 +55,13 @@
           "prerequisites": ["variables", "data-types"],
           "description": "Structured data with named properties",
           "triggers": ["{}", "key:", "value", "property"]
+        },
+        "python": {
+          "name": "Python",
+          "xp_to_master": 100,
+          "prerequisites": ["variables", "functions"],
+          "description": "Python language syntax and conventions",
+          "triggers": [".py", "def ", "print(", "import ", "pip ", "__name__"]
         }
       }
     },
@@ -125,6 +132,13 @@
           "prerequisites": ["html", "js-basics"],
           "description": "Changing the page with JavaScript",
           "triggers": ["document.", "getElementById", "querySelector", "addEventListener"]
+        },
+        "typescript": {
+          "name": "TypeScript",
+          "xp_to_master": 150,
+          "prerequisites": ["js-basics"],
+          "description": "JavaScript with static types for catching bugs early",
+          "triggers": [".ts", ".tsx", "interface", "type ", ": string", ": number", ": boolean"]
         }
       }
     },
@@ -244,6 +258,13 @@
           "prerequisites": ["routes", "json"],
           "description": "Designing and consuming APIs",
           "triggers": ["GET", "POST", "PUT", "DELETE", "fetch(", "axios"]
+        },
+        "testing": {
+          "name": "Testing",
+          "xp_to_master": 150,
+          "prerequisites": ["functions", "js-basics"],
+          "description": "Automated tests that verify code works correctly",
+          "triggers": ["jest", "vitest", "describe(", "it(", "test(", "expect(", ".test.", ".spec."]
         }
       }
     },

data/quiz-bank.json

@@ -84,6 +84,13 @@
         "correct": 1,
         "explanation": "useState creates LOCAL memory for that specific component. When the state changes, React automatically re-draws that component with the new data. It's not permanent (refreshing the page resets it) and it's not global (other components can't see it directly).",
         "hint": "Think of it as the component's personal notebook — only it can read and write to it."
+      },
+      {
+        "belt": "orange",
+        "format": "free_response",
+        "question": "In your own words, why does React use components instead of putting everything in one big file?",
+        "expected_understanding": "Components are reusable building blocks. They make code organized, maintainable, and reusable. Each component handles one piece of the UI.",
+        "hint": "Think about LEGO blocks vs. carving a statue from one piece of stone."
       }
     ],
     "routes": [
@@ -146,7 +153,7 @@
         "hint": "Think about entering a secure building: first they check your identity, then they check your access level."
       }
     ],
-    "javascript": [
+    "js-basics": [
       {
         "belt": "yellow",
         "question": "Why does Claude add `console.log()` statements when debugging?",
@@ -163,15 +170,6 @@
         "hint": "Think about what 'constant' means in everyday language."
       }
     ],
-    "react": [
-      {
-        "belt": "orange",
-        "format": "free_response",
-        "question": "In your own words, why does React use components instead of putting everything in one big file?",
-        "expected_understanding": "Components are reusable building blocks. They make code organized, maintainable, and reusable. Each component handles one piece of the UI.",
-        "hint": "Think about LEGO blocks vs. carving a statue from one piece of stone."
-      }
-    ],
     "typescript": [
       {
         "belt": "orange",