chore: publish @altimateai/drivers package to npm

[anandgupta42]

Context

PR #221 extracted the 10 database drivers into packages/drivers/ as @altimateai/drivers (workspace package). Currently it's private and consumed via workspace:* by packages/opencode.

What

Publish @altimateai/drivers to npm so altimate-mcp-engine and other consumers can use the same driver code instead of maintaining separate implementations.

Tasks

• Add build step (tsup or tsc) to compile to dist/
• Set "private": false and add publishConfig
• Add CI workflow to publish on version tag
• Add README with usage examples
• First publish as @altimateai/drivers@0.1.0

Dependencies

• Depends on PR feat: eliminate Python altimate-engine — all 73 methods native TypeScript #221 being merged first

[anandgupta42]

Deferred — using workspace:* for now. Will publish when altimate-mcp-engine needs it.