Fix PostgreSQL initialization by downgrading gorm

[zhenghaoz]

Close #1070

[Copilot]

Pull Request Overview

This PR fixes PostgreSQL initialization issues by downgrading GORM and related dependencies. The changes address compatibility problems that were preventing proper PostgreSQL database initialization.

• Downgraded GORM from v1.25.7 to v1.23.6 and related database drivers
• Simplified PostgreSQL connection logic by removing pgx/v5 direct usage
• Removed timezone conversion code that may have been causing issues

Reviewed Changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated no comments.

File	Description
go.mod	Downgraded GORM and database drivers, updated various dependency versions
storage/cache/database.go	Simplified PostgreSQL connection by using otelsql.Open instead of pgx directly
storage/cache/sql.go	Removed timezone conversion logic for timestamps
storage/data/database_test.go	Added basic initialization test

Comments suppressed due to low confidence (1)

go.mod:1

• Several golang.org/x/* package versions appear to be from future releases that may not exist yet. Please verify these versions are available or use known stable versions.

module github.com/gorse-io/gorse

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