fix: remove .env.local from git and add .env.example

Remove credentials file from git tracking and provide template for
environment variables.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,3 @@
+AUTH_USERNAME=
+AUTH_PASSWORD=
+RESOURCE_PATH=

.env.local

@@ -1,3 +0,0 @@
-AUTH_USERNAME=admin
-AUTH_PASSWORD=changeme
-RESOURCE_PATH=/Users/tech/workspace/n3-world/handy-tools/ftdl

.gitignore

@@ -32,7 +32,6 @@ yarn-error.log*
 
 # env files (can opt-in for committing if needed)
 .env*.local
-!.env.local
 
 # vercel
 .vercel