Add CHANGELOG.md and update changelog entry

Add an initial feature-history entry to CHANGELOG.md and include CHANGELOG.md in package.json's files list so the changelog is packaged with releases. This records the new feature-history line and ensures the changelog is distributed to consumers.

Author: PatrickJS

CHANGELOG.md

@@ -78,3 +78,4 @@ GitHub repository: <https://github.com/PatrickJS/jsondb>.
 - 2026-05-07 - Ignored the temporary folder in git. Commit [ad4e52a](https://github.com/PatrickJS/jsondb/commit/ad4e52aac9ba2dc39eb320ec4262d660dfb7f2c3).
 - 2026-05-11 - Bumped `actions/setup-node` from v4 to v6. Commit [d4b23e4](https://github.com/PatrickJS/jsondb/commit/d4b23e4dd614c9367e4dbb512755124384fb5918).
 - 2026-05-11 - Bumped `actions/checkout` from v4 to v6. Commit [7dffcc0](https://github.com/PatrickJS/jsondb/commit/7dffcc0c70d5173fddf07ac23737a22dcabb9e49).
+- 2026-05-11 - Added the initial feature-history changelog. Commit [1611bde](https://github.com/PatrickJS/jsondb/commit/1611bde01d3f972a7bb9cae55e9e3f12bb46f45a).

package.json

@@ -46,6 +46,7 @@
     "examples/*/jsondb.config.mjs",
     "examples/*/src/generated/**",
     "jsondb.config.example.mjs",
+    "CHANGELOG.md",
     "README.md",
     "SPEC.md"
   ],