Fix markdownlint errors in learn section

- Deduplicate heading in lesson-02 (specifications)
- Disable MD024 for lesson-03 (repeated component spec structure)
- Fix bare URL in tutorial-11

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

docs/learn/module-07-design-phase/lesson-02-why-specifications-matter.md

@@ -754,7 +754,7 @@ Many methodologies exist. What makes WDS different?
 
 ---
 
-## Your App Exists in Specifications
+## Remember: Your App Exists in Specifications
 
 **Let this sink in:**
 

docs/learn/module-11-conceptual-specifications/lesson-03-element-state-specifications.md

@@ -1,3 +1,4 @@
+<!-- markdownlint-disable MD024 -->
 # Module 11: Conceptual Specifications
 
 ## Lesson 3: Element & State Specifications

docs/learn/module-11-conceptual-specifications/tutorial-11.md

@@ -116,7 +116,7 @@ Transform curious visitors into registered users.
 > "Let's specify each element. Starting with the email field — what are the details?"
 
 **You respond:**
-> "Text input, label says 'Email', placeholder 'you@example.com', validates email format, error message 'Please enter a valid email'."
+> "Text input, label says 'Email', placeholder '`you@example.com`', validates email format, error message 'Please enter a valid email'."
 
 **Freya documents:**
 ```markdown