Site audit: fix broken images, add activity metadata, clean up content

- Remove broken image references from 25 MDX files (deleted spacer/content images)
- Add codingSkills and roverConcepts frontmatter to 24 activity pages
- Fix "Activity Demonstration" headings in 15 activity files (plain text -> h3)
- Remove unused "All" category from 89 MDX files
- Decode HTML entities (> <  ) in 9 content files
- Escape bare < > characters in MDX to fix build errors
- Standardize contact email to contact@micromelon.com.au
- Add missing description to rover-repair-request metadata
- Include previous session work: about-us updates, difficulty filtering,
  LearningPathway component, expanded schools list, new product/resource images

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

content/resources/creating-a-maze-unit.mdx

@@ -1,7 +1,7 @@
 ---
 title: "Creating A Maze Solving Unit For Your Digital Technologies Class"
 date: "2021-07-10"
-categories: ["All"]
+categories: []
 tags: []
 excerpt: "How to do maze solving in your digital technologies classroom."
 featuredImage: "/images/resources/creating-a-maze-unit.png"
@@ -17,15 +17,13 @@ Maze challenges are great cumulative activities for digital technologies classes
 
 - How to build your student's knowledge throughout the term so they are ready to attempt maze assessments.
 
-![](/images/content/1cf38b-maze.png)
-
 ### **What Skill Level Are Mazes Appropriate For?**
 
 Mazes can be a great challenge for students of all skill levels. Maze complexity can be adjusted easily with changes to layout and the optional inclusion of various challenges. As the maze becomes more complex, the algorithm students create will become more sophisticated. You can tailor a maze to meet the desired learning objectives necessary for your student’s skill level.
 
 ### Possible Maze Unit Learning Objectives
 
-**Branching, Iteration & Algorithm Design** To complete a maze, students will need to design an algorithm for their Rover. The algorithm will instruct the Rover how to handle path formations and maze challenges. Successful maze algorithms will require students to have a comprehensive understanding of branching and iteration. The more complex the maze, the more sophisticated the algorithm required to solve the maze will need to be. Maze algorithms will typically implement comprehensive branching logic using ** IF / Else / Else If** blocks and ** conditional operator (>, <, ==, !=)** blocks. Branching logic will often need to be repeated, this is done using a variety of** Loops**.
+**Branching, Iteration & Algorithm Design** To complete a maze, students will need to design an algorithm for their Rover. The algorithm will instruct the Rover how to handle path formations and maze challenges. Successful maze algorithms will require students to have a comprehensive understanding of branching and iteration. The more complex the maze, the more sophisticated the algorithm required to solve the maze will need to be. Maze algorithms will typically implement comprehensive branching logic using ** IF / Else / Else If** blocks and ** conditional operator (`>`, `<`, `==`, `!=`)** blocks. Branching logic will often need to be repeated, this is done using a variety of** Loops**.
 
 **Understanding & Analysing Sensor Data** Depending on maze complexity, there are a range of sensors students can use to solve challenges and optimize their algorithm. Most common mazes will require students to utilize the Rovers ** ultrasonic**,** IR ** and** colour sensors**. The** IR and ultrasonic sensors ** will be used to detect the walls of the maze. The** colour sensors ** are used to detect changes to floor colour e.g. to detect when the rover finds the finish point or an obstacle. More complex solutions may also make use of the** gyroscope**.
 
@@ -219,8 +217,6 @@ Knowing the science behind how the ultrasonic & IR sensors work provides student
 
 [Read More](/resources/ir-sensor)
 
-![](/images/content/75c9e0-ultrasonic-animation.gif)
-
 Basics Of The Ultrasonic Sensor
 
 [Read More](/resources/ultrasonic-sensor)