chore: establish M0 project foundations

Document accepted MVP decisions, add AGPL-3.0-only licensing, scaffold repository boundaries, and configure verified PSR-12 and foundation checks.

Refs #1, #2, #3, #4, #5

.gitignore

@@ -1,2 +1,24 @@
 notes/
 .superpowers/
+
+/vendor/
+node_modules/
+/public/build/
+/build/
+/dist/
+/coverage/
+/.phpunit.cache/
+/.phpunit.result.cache
+/.phpcs-cache
+
+.env
+.env.*
+!.env.example
+/auth.json
+*.log
+
+# Default local runtime locations; never put user libraries in source control.
+/var/
+/storage/
+/library/
+/pgdata/