feat: Multi-Database Support (Postgres/SQLite/SQL Server) + One-Command Installers + CI/CD

[Opselon]

🎯 Summary

Full multi-database architecture with zero-config startup — the app now supports PostgreSQL, SQLite, and SQL Server out of the box, with an interactive wizard on first run.

✅ What's New

Multi-Database Engine

• DatabaseProviderConfigurator — single source of truth for EF Core + Hangfire provider selection, schema translation, and database creation
• Automatic type translation: nvarchar(max)→TEXT, GETUTCDATE()→NOW()/datetime('now'), uniqueidentifier→uuid, etc.
• Tested end-to-end on all three databases ✅

First-Run Wizard (FirstRunSetup.cs)

• Interactive: colored menu asking DB choice + connection params (passwords masked)
• Non-interactive (Docker/CI): reads env vars, defaults to SQLite

Fail-Soft Startup

• App starts cleanly without any Telegram config — no crash, no 100s hang
• 3-layer resilience: client constructor, init service, bot service

One-Command Installers

• install.sh — Linux/macOS (Docker or native path)
• install.ps1 — Windows PowerShell (Docker or native)
• Both auto-detect dependencies and guide through setup

CI/CD Workflows

• ci.yml — build + test on every push/PR
• release.yml — tag-triggered: 4-platform publish + Docker image + GitHub Release

Infrastructure

• Multi-stage Dockerfile (sdk → alpine runtime, non-root)
• .dockerignore, healthcheck improvements, idempotent init.sql
• Comprehensive README.md with quick-start guide

🧪 Test Results

• 42 tests pass (41 new for DatabaseProviderConfigurator + 1 existing)
• End-to-end verified: SQLite ✅ | PostgreSQL ✅ | SQL Server ✅

📁 Files Changed

29 files, +2462 / -195

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[Opselon]

Closing in favor of PR #46, which is rebased on the real default branch (master) and contains only the genuine delta. This PR was based on the stale main branch (626 commits behind master) and its feature is largely already implemented in master (EasySetupWizard + DatabaseProvider enum + multi-storage Hangfire).