chore: initialize repository with project docs and tooling

- Add persistent docs: PRD, functional design, architecture, repository structure, development guidelines, milestones

- Add brainstorming notes (docs/ideas/)

- Configure tooling: package.json, tsconfig, eslint, prettier, vitest

- Add opencode configuration (commands, skills, agents)

- Add .gitignore for node_modules, .env, data/, backups/, build outputs

.gitignore

@@ -0,0 +1,57 @@
+# Temporary files
+tmp/
+
+# Node.js
+node_modules/
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Build outputs
+dist/
+build/
+.next/
+*.tsbuildinfo
+
+# App data (SQLite DB + uploads)
+data/
+
+# Backups
+backups/
+
+# Playwright
+test-results/
+playwright-report/
+
+# Environment variables
+.env
+.env.local
+.env.*.local
+
+# Logs
+logs/
+*.log
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# Testing
+coverage/
+.nyc_output/
+
+# Steering files (task management - temporary)
+.steering/*
+!.steering/.gitkeep
+
+# Lock files (keep package-lock.json for consistency)
+# yarn.lock
+
+.opencode/opencode.local.json