Fix Windows CI library linking errors with conditional compilation for database backends

[Copilot]

Windows CI fails with Error: Cannot locate the .lib files for the following libraries: sqlite3, rocksdb because DISABLE_SQLITE3=1 is set in CI but not implemented in the codebase—sqlite3 and pg are unconditionally required.

Changes

src/atomspace/storage.cr

• Wrap require "sqlite3" and require "pg" with compile-time macros checking DISABLE_SQLITE3 and DISABLE_POSTGRES env vars
• Add stub implementations for SQLiteStorageNode and PostgresStorageNode when disabled (following existing rocksdb.cr pattern)
• Add MemoryStorageNode as in-memory fallback when all DB backends are disabled

.github/workflows/crci.yml

• Add DISABLE_POSTGRES=1 for Windows builds
• Add libpq-dev to Linux dependencies

Documentation

• Update shard.yml and README.md with DISABLE_* env var documentation

Usage

# Disable all database backends (Windows builds, testing)
DISABLE_ROCKSDB=1 DISABLE_SQLITE3=1 DISABLE_POSTGRES=1 crystal spec

# Use MemoryStorageNode as fallback
storage = AtomSpace::MemoryStorageNode.new("test")
storage.open

---

Note

Medium Risk
Changes compile-time linking and the persistence surface area (stubs vs real DB code), but behavior on Linux with libs installed should stay the same; risk is mainly misconfigured builds or tests that still expect SQLite/Postgres when disabled.

Overview
Fixes Windows CI link failures by making SQLite and PostgreSQL optional at compile time, matching the existing RocksDB DISABLE_* pattern.

In storage.cr, require "sqlite3" and require "pg" are wrapped in compile-time checks for DISABLE_SQLITE3 and DISABLE_POSTGRES. When a backend is disabled, the full implementation is replaced with stub SQLiteStorageNode / PostgresStorageNode classes that warn on construction and raise if persistence APIs are used. A new MemoryStorageNode provides a mutex-backed in-memory StorageNode for tests and builds with no native DB libs.

CI sets DISABLE_POSTGRES=1 on Windows alongside the existing RocksDB/SQLite flags, and Linux installs libpq-dev. README and shard.yml document all three disable env vars and point to MemoryStorageNode / FileStorageNode when DB backends are off.

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[cursor]

Disabled stub open raises

Medium Severity

When SQLite or PostgreSQL is compile-disabled, their stub StorageNode implementations raise exceptions from methods like open rather than returning a boolean. This can cause runtime crashes in higher-level storage nodes expecting a graceful false return.

 

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