refactor: reorganize into monorepo with separate subprojects

Structure webber into three independent subprojects:
- webber-api/: FastAPI backend server with all agent code
- webber-cli/: Standalone CLI client (renamed from cli/ to webber_cli/)
- webber-sandbox/: Test project for functional testing

Key changes:
- Each subproject has its own .venv (Python 3.12+)
- Added sandbox.sh for managing test project templates
- Created sandbox-templates/ with calculator-cli and empty starter
- Updated CI/CD for prefixed tags (api/v*, cli/v*)
- Added comprehensive AGENTS.md with operational instructions
- Added gitignore filtering to glob and grep tools
- Created pyproject.toml for each subproject

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

webber-api/.env.example

@@ -0,0 +1,31 @@
+# Webber Configuration
+# Copy to .env and customize
+
+# Application
+DEBUG=true
+LOG_LEVEL=DEBUG
+
+# Server
+HOST=0.0.0.0
+PORT=8086
+
+# CORS (comma-separated)
+CORS_ORIGINS=["http://localhost:3000","http://localhost:8080"]
+
+# LLM - Ollama (tower-of-joy)
+OLLAMA_URL=http://192.168.86.149:11434
+OLLAMA_AGENT_MODEL=mistral-nemo-large:latest
+OLLAMA_EMBED_MODEL=nomic-embed-text:latest
+
+# Auth - Tatlock integration (optional)
+# TATLOCK_API_URL=http://192.168.86.149:8000
+# INTERNAL_API_KEY=your-internal-key
+
+# Tool execution
+TOOL_TIMEOUT_SECONDS=120
+SANDBOX_ENABLED=true
+# ALLOWED_PATHS=["/home/user/projects","/tmp/webber"]
+
+# Sessions
+SESSION_TTL_HOURS=24
+MAX_CONTEXT_TOKENS=128000