🐛 Stop knip reporting the source entry

Listing scripts/*.ts in knip's `entry` replaced its default entry
detection, which derives the public entry from package.json `exports`.
Adding the CLI scripts therefore dropped the library entry, so knip
resolved the package through dist/index.js and flagged the unreferenced
src/index.ts as unused. Name the source entry alongside the scripts.

Record the rationale in development/tooling.md.

knip.json

@@ -1,5 +1,5 @@
 {
     "$schema": "./node_modules/knip/schema.json",
-    "entry": ["scripts/*.ts"],
+    "entry": ["src/index.ts", "scripts/*.ts"],
     "ignoreDependencies": ["@runwisp/pubv"]
 }