refactor: relocate AI SDK module to lib/sdk/server-ai (AIC-2661)

Place the module under lib/sdk/ alongside the core SDK (lib/sdk/server),
mirroring the JS reference layout (packages/sdk/server-ai), instead of the
flat lib/java-server-sdk-* add-on pattern. Maven coordinates are unchanged
(com.launchdarkly:launchdarkly-java-server-sdk-ai). Updates CI workspace_path
and release-please manifest/config keys to the new path.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: ctawiah

.github/workflows/java-server-sdk-ai.yml

@@ -22,5 +22,5 @@ jobs:
       - name: Shared CI Steps
         uses: ./.github/actions/ci
         with:
-          workspace_path: 'lib/java-server-sdk-ai'
+          workspace_path: 'lib/sdk/server-ai'
           java_version: ${{ matrix.java-version }}

.release-please-manifest.json

@@ -1,5 +1,5 @@
 {
-  "lib/java-server-sdk-ai": "0.1.0",
+  "lib/sdk/server-ai": "0.1.0",
   "lib/java-server-sdk-otel": "0.2.0",
   "lib/java-server-sdk-redis-store": "3.1.1",
   "lib/shared/common": "2.4.0",