chore: add MIT LICENSE and harden gitignore

.gitignore

@@ -1,6 +1,19 @@
 # Local configuration (machine-specific paths, do not commit)
 manager-config.json
 
+# Env files / secrets (never commit)
+.env
+.env.*
+!.env.example
+
+# Credentials / keys (never commit)
+credentials/
+**/credentials/
+*.pem
+*.key
+id_rsa
+id_ed25519
+
 # OpenClaw config backups
 *.bak
 *.bak.*
@@ -27,4 +40,4 @@ Desktop.ini
 node_modules/
 npm-debug.log*
 yarn-error.log*
-.env.local
+

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Tao Deng
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.