Migrate to better-auth 1.5.3+ (drizzle adapter moved to separate package)

[jhaynie]

Summary

better-auth@1.5.3 introduced a breaking change where @better-auth/drizzle-adapter was moved from a bundled dependency to an optional peer dependency. This means the import path better-auth/adapters/drizzle no longer exists in 1.5.3+.

We've pinned better-auth to 1.5.2 as a temporary fix (commit 86d56f8a on release/1.0.34). This issue tracks the proper migration.

Breaking Change Details

	1.5.2 (working)	1.5.3 (broken)
@better-auth/drizzle-adapter	Bundled as a direct dependency	Optional peer dependency
better-auth/adapters/drizzle path	✅ Exists, exports drizzleAdapter	❌ Does not exist
New import path	N/A	@better-auth/drizzle-adapter

Affected Files

1. packages/drizzle/src/index.ts (line 128)

   export { drizzleAdapter } from 'better-auth/adapters/drizzle';

2. packages/auth/src/agentuity/config.ts (line 10)

   import { drizzleAdapter } from 'better-auth/adapters/drizzle';

Migration Steps

1. Add @better-auth/drizzle-adapter@^1.5.3 as a dependency in packages/drizzle/package.json and packages/auth/package.json
2. Update imports from better-auth/adapters/drizzle → @better-auth/drizzle-adapter
3. Verify the exported API name is still drizzleAdapter (or update accordingly)
4. Unpin better-auth from 1.5.2 back to ^1.5.0 (or ^1.5.3)
5. Unpin @better-auth/api-key from 1.5.2 back to ^1.5.0
6. Run full build + typecheck + tests

Current Pinned Versions (to be reverted)

• packages/drizzle/package.json: "better-auth": "1.5.2"
• packages/auth/package.json: "better-auth": "1.5.2", "@better-auth/api-key": "1.5.2"

Context

• CI failure: https://github.com/agentuity/sdk/actions/runs/22693392001/job/65794197625?pr=1116
• Fix PR: Release 1.0.34 #1116
• Error: TS2305: Module '"better-auth/adapters/drizzle"' has no exported member 'drizzleAdapter'

[linear]

AGENT-1423