feat: add quick install script and packaging (#197)

Give bot-bottle a real distribution path so new users can install
without cloning the repo:

- pyproject.toml: full project metadata, a `bot-bottle` console-script
  entry point (bot_bottle.cli:main), and package-data for the runtime
  assets (Dockerfiles, egress entrypoint, netpool defaults, macos init).
  Still zero runtime pip dependencies.
- install.sh: POSIX, sudo-free, idempotent bootstrapper — checks Python
  >= 3.11, creates ~/.bot-bottle/{agents,bottles,contrib}, installs via
  pipx (pip --user fallback), then runs `bot-bottle doctor`.
- `bot-bottle doctor`: new store-free subcommand reporting Python
  version, backend availability (reuses is_backend_available rather than
  hardcoding Docker), and config-dir presence. Exits non-zero when a hard
  prerequisite is unmet.
- PRD prd-new-install-script and unit tests for doctor, the packaging
  contract, and the install script.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pyproject.toml

@@ -4,5 +4,42 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "bot-bottle"
-version = "0.0.0"
+version = "0.1.0"
+description = "Self-hosted sandbox for running AI coding agents with egress controls"
+readme = "README.md"
 requires-python = ">=3.11"
+license = { text = "Apache-2.0" }
+authors = [{ name = "didericis" }]
+keywords = ["ai", "agents", "sandbox", "security", "egress"]
+classifiers = [
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3 :: Only",
+    "Operating System :: POSIX :: Linux",
+    "Operating System :: MacOS",
+]
+# The package itself has no runtime pip dependencies (stdlib-only); the
+# only language runtime is the Python interpreter. Keep this empty.
+dependencies = []
+
+[project.urls]
+Homepage = "https://gitea.dideric.is/didericis/bot-bottle"
+Source = "https://gitea.dideric.is/didericis/bot-bottle"
+
+[project.scripts]
+bot-bottle = "bot_bottle.cli:main"
+
+[tool.setuptools.packages.find]
+include = ["bot_bottle*"]
+
+# Non-Python assets the runtime reads from inside the package (container
+# build contexts, entrypoints, netpool defaults). Keep in sync with the
+# files shipped under bot_bottle/; test_pyproject.py asserts they exist.
+[tool.setuptools.package-data]
+bot_bottle = [
+    "egress_entrypoint.sh",
+    "contrib/claude/Dockerfile",
+    "contrib/codex/Dockerfile",
+    "contrib/pi/Dockerfile",
+    "backend/firecracker/netpool.defaults.env",
+    "backend/macos_container/nested-containers-init.sh",
+]