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-cli/pyproject.toml

@@ -0,0 +1,40 @@
+[project]
+name = "webber-cli"
+version = "0.1.0"
+description = "Webber CLI - Command-line client for Webber API"
+authors = [
+    {name = "jpmschweitzer"}
+]
+readme = "README.md"
+requires-python = ">=3.12"
+license = {text = "MIT"}
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Environment :: Console",
+    "Programming Language :: Python :: 3.12",
+    "Topic :: Software Development :: Code Generators",
+]
+
+[project.scripts]
+webber-cli = "webber_cli.main:app"
+
+[build-system]
+requires = ["setuptools>=75.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["webber_cli*"]
+
+[tool.ruff]
+target-version = "py312"
+line-length = 100
+src = ["webber_cli"]
+
+[tool.ruff.lint]
+select = ["E", "W", "F", "I", "B", "C4", "UP", "SIM"]
+ignore = ["E501"]
+
+[tool.ruff.format]
+quote-style = "double"
+indent-style = "space"