store/queries: Address technical debt and minor issues

[drahnr]

Derived from comments on #1148

Related to #1134

Code Organization

1. File Structure
   • Suggestion to further split files under namespaces (e.g., notes/mod.rs, notes/network_notes.rs)
   • Consider moving insert statements from insertions.rs to their corresponding entity files
   • Consider grouping test-specific functions in separate sections

Documentation

• Add missing function docs
• Move SQL statements to doc comments
• Document parameter limits

Performance Considerations

1. Data Structures

2. Query Optimization

   • Some complex queries (like note selection) might need optimization
   • Consider splitting complex queries into separate functions
   • Need to address potential scalability issues with large result sets

3. Data Storage

   • Need to optimize nullifier tree rebuilding for large datasets #1202
   • Upgrade to large capacity SMT #1189 / Consider migrating to LargeSmt for better scalability

Technical Debt

1. Naming Conventions

   • Normalize parameter naming (e.g., block_from/block_to instead of various alternatives)
   • Improve consistency in parameter naming across different queries

2. Error Handling

   • Ensure proper limit checks on all query parameters
   • Add missing parameter limit checks for some functions