feat: add matching exercise

[AngelsandDevsLOL]

Proposed Changes

Adds the matching exercise at /matching-exercise, where the user draws wires between component chips and their descriptions

What it does:

• Two columns: component chips on the left, descriptions on the right, with an SVG wire layer drawn between them
• A wire that may start from any Component or Description piece and snap to another piece. Each piece holds at most one wire, so a new connection replaces whatever was already attached to either end
• Check my work / Reset, scoring, and a results sidebar listing the components that were matched incorrectly

Refactoring between previous /exercise and current /matching-exercise:

• ComponentPieces moved from components/exercise/ to components/common/
• The side bar panel (score ring, incorrect list, retry) extracted from ExerciseBoardSidebar into a shared ExerciseResultsPanel.
• Matching-exercise types (Point, Side, Anchor, Wire, WireSegment) are refactored into components/matching-exercise/types.ts

Works on #41

Screenshots of your changes (if applicable)

Type of Change

(Write an X or a brief description next to the type or types that best describe your changes.)

Type	Applies?
🚨 Breaking change (fix or feature that would cause existing functionality to change)
✨ New feature (non-breaking change that adds functionality)	X
🐛 Bug fix (non-breaking change that fixes an issue)
🎨 User interface change (change to user interface; provide screenshots)	X
♻️ Refactoring (internal change to codebase, without changing functionality)	X
🚦 Test update (change that only adds or modifies tests)
📦 Dependency update (change that updates a dependency)
🔧 Internal (change that only affects developers or continuous integration)

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Questions and Comments

[matt-dahlgren]

All of this looks so good!