Implement new exercises on expressions, variables, and control flow

- Add exercises for expressions and output, including logging and string manipulation.
- Introduce variable assignments and reassignment concepts.
- Create control flow exercises focusing on conditionals and loops.
- Update README and FINISHED files to guide learners through new content.
- Ensure consistency in TypeScript type annotations across exercises.

Author: kentcdodds

exercises/01.expressions-and-output/01.problem.hello-world/README.mdx

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+# Hello World
+
+👨‍💼 Every programmer starts here: printing "Hello, World!" to the screen.
+
+The `console.log()` function takes a value and prints it to the terminal. This
+is how you see the results of your code.
+
+🐨 Open <InlineFile file="index.ts" /> and complete the following tasks:
+
+1. Use `console.log()` to print the string `"Hello, World!"`
+2. Use `console.log()` to print your name as a string
+
+💰 Strings are text values wrapped in quotes:
+
+```ts
+console.log('This is a string')
+console.log('Double quotes work too')
+```
+
+🐨 Once you've completed the exercise, run `node index.ts` in the playground to
+see your output!

exercises/01.expressions-and-output/01.problem.hello-world/index.ts

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+// Your First Program
+// Let's print some messages to the console!
+
+// 🐨 Use console.log() to print "Hello, World!"
+
+// 🐨 Use console.log() to print your name (as a string)
+
+export {}

exercises/01.expressions-and-output/01.problem.hello-world/package.json

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+{
+  "name": "exercises_01.expressions-and-output_01.problem.hello-world",
+  "type": "module",
+  "scripts": {
+    "start": "node index.ts",
+    "test": "node --test index.test.ts"
+  }
+}

exercises/01.expressions-and-output/01.solution.hello-world/README.mdx

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+# Hello World
+
+👨‍💼 You did it! You've written your first lines of code.
+
+`console.log()` is one of the most useful tools you have. Whenever you're
+confused about what a value is, just log it!
+
+🦉 Notice that strings can use either single quotes (`'`) or double quotes
+(`"`). In this workshop, we'll use single quotes, but both work identically.

exercises/01.expressions-and-output/01.solution.hello-world/index.test.ts

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+import assert from 'node:assert/strict'
+import { execSync } from 'node:child_process'
+import { test } from 'node:test'
+
+await test('should print Hello, World!', () => {
+	const output = execSync('node index.ts', { encoding: 'utf8' })
+	assert.ok(
+		output.includes('Hello, World!'),
+		'🚨 Output should include "Hello, World!" - make sure you used console.log() with that exact string',
+	)
+})
+
+await test('should print at least two lines', () => {
+	const output = execSync('node index.ts', { encoding: 'utf8' })
+	const lines = output.trim().split('\n').filter(Boolean)
+	assert.ok(
+		lines.length >= 2,
+		'🚨 Output should have at least 2 lines - make sure you logged both Hello, World! and your name',
+	)
+})

exercises/01.expressions-and-output/01.solution.hello-world/index.ts

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+// Your First Program
+// Let's print some messages to the console!
+
+console.log('Hello, World!')
+
+console.log('Kody')
+
+export {}

exercises/01.expressions-and-output/01.solution.hello-world/package.json

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+{
+  "name": "exercises_01.expressions-and-output_01.solution.hello-world",
+  "type": "module",
+  "scripts": {
+    "start": "node index.ts",
+    "test": "node --test index.test.ts"
+  }
+}

exercises/01.expressions-and-output/02.problem.strings/README.mdx

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+# String Expressions
+
+👨‍💼 Strings are one of the most common types of data in programming. Let's
+explore what you can do with them.
+
+You can combine strings together using the `+` operator. This is called
+**concatenation**:
+
+```ts
+console.log('Hello' + ' ' + 'World') // Prints: Hello World
+```
+
+🐨 Open <InlineFile file="index.ts" /> and complete the following tasks:
+
+1. Log the result of concatenating `"Hello"` and `"TypeScript"` with a space
+   between them
+2. Log your first name and last name concatenated together
+3. Log a longer message by concatenating multiple strings
+
+💰 Remember to include spaces where you need them - the `+` operator joins
+strings exactly as they are!

exercises/01.expressions-and-output/02.problem.strings/index.ts

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+// String Expressions
+// Learn to work with text data
+
+// 🐨 Log "Hello" + " " + "TypeScript" (concatenate these three strings)
+
+// 🐨 Log your first name and last name concatenated together with a space
+
+// 🐨 Log a sentence by concatenating multiple strings
+// 💰 Example: "I" + " " + "am" + " " + "learning" + " " + "to" + " " + "code"
+
+export {}

…/01.solution.void-functions/package.json …d-output/02.problem.strings/package.jsonexercises/05.void-and-never/01.solution.void-functions/package.json renamed to exercises/01.expressions-and-output/02.problem.strings/package.json exercises/05.void-and-never/01.solution.void-functions/package.json renamed to exercises/01.expressions-and-output/02.problem.strings/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "exercises_05.void-and-never_01.solution.void-functions",
+  "name": "exercises_01.expressions-and-output_02.problem.strings",
   "type": "module",
   "scripts": {
     "start": "node index.ts",