[Feature]: Add PBS reagent template example

[lichangda94-sys]

Feature summary

Add a PBS reagent template example to demonstrate how reagent templates should be structured, scaled, documented, and tested.

Related module

Reagent tools

Problem or workflow need

PBS is one of the most common laboratory buffers. A clear PBS template example would help users understand how BioMedPilot-LabTools handles reagent components, target volume scaling, pH records, solvent top-up, and preparation-stage logic.

Proposed solution

Add a PBS reagent template example under the examples directory. The example should include component names, amounts, units, target volume, pH record, solvent/top-up information, and addition order or preparation-stage information.

The template should be simple enough for new contributors to understand and should be usable as a reference for future reagent templates.

Formula or calculation logic

Component amounts should scale proportionally with target preparation volume.

For example, if the base template is for 1 L PBS, preparing 100 mL should multiply scalable components by 0.1.

Solvent or water should be treated as top-up to final target volume rather than as a fixed component when appropriate.

Expected inputs and outputs

Inputs:

• Target preparation volume
• Volume unit
• Optional waste percentage or fixed extra volume

Outputs:

• Scaled component amounts
• Solvent/top-up instruction
• pH record if included
• Preparation-stage steps

Example use case

A user wants to prepare 100 mL PBS from a saved PBS template.

The tool should calculate scaled component amounts from the base template and show clear preparation instructions, including water/top-up and pH information if available.

References or notes

The example should avoid claiming that a single PBS recipe is universal. It should be presented as an example template that users must review and adapt to their own laboratory SOP.

Scope check

• This request is for research or laboratory workflow assistance, not clinical diagnosis or treatment decisions.
• I have not included patient data, private laboratory records, API keys, credentials, or confidential protocols.