Extend SQLite schema and implement migration

[VellummyilumVinoth]

Description

It Resolves wso2/product-ballerina-integrator#1909, wso2/product-ballerina-integrator#2251, wso2/product-ballerina-integrator#2252, wso2/product-ballerina-integrator#2253

This PR migrates the Copilot Library Service from static JSON-based library definitions to a SQLite search index–based architecture and improves package metadata extraction and service modeling.

The system now uses a database-driven approach for library and package information, making it more scalable, maintainable, and aligned with the BI package ecosystem.

Key Changes

New Service Implementation

• Queries search-index.sqlite instead of static JSON files
• Provides dynamic and structured package metadata retrieval

New Extension Classes

• Retrieves library lists from the SQLite search index
• Filters libraries using the Semantic Model API

Enhanced Metadata Handling

• Added new metadata models:

  • FieldData.java
  • ReturnTypeData.java
  • TypeDefData.java

• Enhanced FunctionDataBuilder.java to improve function and type modeling

These changes improve representation of types, fields, function signatures, and return structures.

Database and Schema Updates

• Migrated from central-index.sqlite to search-index.sqlite as the primary data source
• search-index.sqlite size increased (~17MB to ~18MB) due to richer metadata
• Added search-index.sql schema definition
• Updated generic-services.json with service definitions

[xlight05]

About get_filtered_libraries.json, seems like we are asserting the response for http and another library.

We need to make this bit more readable on what we are testing here.

If the idea is to cover set of different libraries (and assume most cases are covered there), we shold have it in the test name.

I'd prefer having multiple test cases, (connector, library, http etc). The idea is that if we break something, we should catch that from tests. We should stratergically cover cases.

[xlight05]

Lets address PR comments in a separate PR to this dev branch.