TiDB Quick Start refresh

[alastori]

What is changed, added or deleted? (Required)

Significantly improved the Quick Start Guide to make it more user-friendly and educational:

• Restructured content to follow a clear learning path
• Added a sample weather monitoring application to demonstrate real-world usage
• Improved monitoring and scaling sections with practical examples
• Added detailed explanations of components and their roles
• Included developer workflow best practices with tagged environments
• Enhanced the guide with monitoring visualization tips
• Added clear "What's next" section with targeted resources
• Improved code examples with proper formatting and explanations
• Added more contextual information about TiDB's capabilities
• Improved navigation and readability

The changes aim to provide a better first-time user experience while maintaining technical accuracy and demonstrating TiDB's key features through practical examples.

Which TiDB version(s) do your changes apply to? (Required)

• master (the latest development version)

What is the related PR or file link(s)?

This PR updates the existing Quick Start Guide with modern documentation best practices and a more comprehensive learning approach.

[ti-chi-bot]

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[ti-chi-bot]

@alastori: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-verify	690e280	link	true	/test pull-verify

Full PR test history. Your PR dashboard.

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[Oreoxmt]

source ~/.bash_profile

The current description is too specific and may mislead users, as shell profile paths can vary across different Linux distributions and shell types. I recommend keeping the original, more flexible instructions:

docs/quick-start-with-tidb.md

Lines 55 to 67 in 063e85c

	Note the Shell profile path in the output above. You need to use the path in the next step.
	2. Declare the global environment variable:
	> **Note:**
	>
	> After the installation, TiUP displays the absolute path of the corresponding Shell profile file. You need to modify `${your_shell_profile}` in the following `source` command according to the path. In this case, `${your_shell_profile}` is `/Users/user/.zshrc` from the output of Step 1.
	{{< copyable "shell-regular" >}}
	```shell
	source ${your_shell_profile}
	```

For example, in the installation output shown below, the shell profile is /home/codespace/.bashrc:

Successfully set mirror to https://tiup-mirrors.pingcap.com
Detected shell: bash
Shell profile:  /home/codespace/.bashrc
/home/codespace/.bashrc has been modified to add tiup to PATH
open a new terminal or source /home/codespace/.bashrc to use it
Installed path: /home/codespace/.tiup/bin/tiup
===============================================
Have a try:     tiup playground
===============================================

open a new terminal or source /home/codespace/.bashrc to use it

[Oreoxmt]

Suggested change

	You should see this output:
	The output is as follows:

should, should be link
Generally avoid.
Because should is ambiguous by definition, it can be problematic.
"If an outcome is expected: Describe the outcome in terms of what is expected. For example: "The process returns 10 items."

https://developers.google.com/style/word-list#should