Docs: User Guide Landing Page

[andrewendlinger]

Is your feature request related to a problem?

The User Guide landing page itself is currently not the most welcoming (unlike e.g. the Gallery):

Describe the solution you'd like

A small intro and a structured toctree could come a long way:

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Happy to turn this into a PR, but I thought I would discuss the toctree structure with you first.

Here is one option:

Data model

• Terminology
• Data Structures

Core operations

• Indexing
• Computation
• GroupBy
• Reshaping
• Combining

I/O & scaling

• I/O
• Dask

Visualization & pandas

• Plotting
• Pandas

Advanced features

• Duckarrays
• Hierarchical Data
• Options
• Testing

Domain‑specific workflows

• Time Series
• Weather & Climate
• Complex Numbers

Describe alternatives you've considered

Alternative

And one alternative:

Core Concepts

• Terminology
• Data Structures

Data Selection & Manipulation

• Indexing
• Reshaping
• Combining
• GroupBy

Computation & Performance

• Interpolation
• Computation
• Dask

Input/Output

• I/O

Visualization

• Plotting

Interoperability & Ecosystem

• Pandas
• Duckarrays

Specialized Applications

• Time Series
• Weather & Climate
• Complex Numbers

Advanced Topics & Configuration

• Hierarchical Data
• Options
• Testing

Additional context

(Already added 'Complex Numbers' as a section, in case #10235 gets merged.)