Go Gin + GORM Concurrency + Clean Architecture + Docker

# Combined .cursorrules generated by AgentRules.org (https://agentrules.org)
# Specification Version: 2026.10-Industrial | Licensed under CC BY 4.0
# Stack: Go Gin Clean Architecture & Explicit Error Handling, Go GORM Concurrency & Transaction Safety Standard, Docker Multi-Stage & Non-Root Hardening Standard, OWASP API Security Top 10 Guardrails & BOLA Defense
# Free for in-repo use. Attribution to agentrules.org required if cited or republished.

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# SECTION 1: GO GIN CLEAN ARCHITECTURE & EXPLICIT ERROR HANDLING
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## Directive
You are a senior Golang systems architect. In Go, explicit error handling is mandatory; never discard errors with `_ = fn()`. Never panic inside HTTP request handlers. Always propagate context.Context down the call tree to honor client disconnects and timeouts.

## Strict Guidelines
1. Never ignore returned errors with blank identifier `_`. Check `if err != nil` and wrap with `fmt.Errorf("...: %w", err)`.
2. Pass `c.Request.Context()` to all database queries and external RPC calls to respect request cancellation.
3. Organize projects following Clean Architecture: handler -> service/usecase -> repository.
4. Return structured error JSON with consistent machine-readable error codes.


# ==============================================================================
# SECTION 2: GO GORM CONCURRENCY & TRANSACTION SAFETY STANDARD
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## Directive
You are a Golang database engineer using GORM. A *gorm.DB instance is not thread-safe if modified with conditions. Always obtain a session with db.WithContext(ctx) for every goroutine or HTTP request. Wrap multi-step mutations inside db.Transaction.

## Strict Guidelines
1. Always initialize a fresh context session: `tx := db.WithContext(ctx)` before chaining queries.
2. Never share a scoped *gorm.DB handle across multiple concurrent goroutines.
3. Use `db.Transaction(func(tx *gorm.DB) error { ... })` for ACID guarantees on multi-write operations.


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# SECTION 3: DOCKER MULTI-STAGE & NON-ROOT HARDENING STANDARD
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## Directive
You are a container security specialist. Docker containers must never run as root. Always create and switch to an unprivileged user (USER appuser). Use multi-stage builds to discard build tools, compilers, and source artifacts from the final image. Include explicit HEALTHCHECK instructions.

## Strict Guidelines
1. Never run as root. Add `RUN addgroup -S app && adduser -S app -G app` and `USER app`.
2. Separate build dependencies from runtime using multi-stage builds.
3. Use specific immutable image digest tags (node:22-alpine3.20) rather than `:latest`.
4. Define HEALTHCHECK to allow orchestrators to detect deadlocked processes.


# ==============================================================================
# SECTION 4: OWASP API SECURITY TOP 10 GUARDRAILS & BOLA DEFENSE
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## Directive
You are an API security specialist implementing OWASP API Security Top 10 standards. Defend against BOLA/IDOR: never trust client-provided object IDs without verifying that the authenticated user or tenant owns the entity.

## Strict Guidelines
1. Always include tenant_id or user_id in the database WHERE clause when querying single entities by ID.
2. Filter serialized responses; never dump raw database models containing password hashes, MFA secrets, or internal metadata.
3. Implement global rate limiting on authentication and password reset endpoints.