fix: make installed wheel self-contained + harden install.sh prereqs

Addresses the review on PR #481.

Self-contained wheel (review point 1): the gateway/infra/orchestrator
images build from a context that must hold bot_bottle/, pyproject.toml,
and the root-level Dockerfiles. Modules previously located these by
walking __file__ to the repo root, so an installed wheel (package in
site-packages, no repo root) passed `doctor` but failed `start`.

- Add bot_bottle/resources.py: build_root() returns the repo root in a
  checkout (unchanged) or a staged copy from the wheel's bundled
  _resources/ otherwise; dockerfile()/nix_netpool_module()/
  netpool_script() derive from it.
- setup.py bundles the root Dockerfiles, nix module, netpool script, and
  pyproject.toml into bot_bottle/_resources/ at build; MANIFEST.in ships
  them in the sdist.
- Route every _REPO_ROOT/_REPO_DIR call site (docker/macos launch, macos
  infra, firecracker infra_vm/infra_artifact/setup, orchestrator
  lifecycle/gateway) through resources. Checkout behavior is unchanged.

install.sh prerequisites (review point 2): check for git when installing
a git+ spec, and — before the pip fallback — that pip is usable and the
interpreter isn't externally managed (PEP 668), pointing at pipx.

Tests: test_resources covers checkout + staged-wheel layouts;
test_wheel_install builds the wheel, installs it into an isolated venv,
and asserts `doctor` runs and build_root() yields a valid context.
Running `start` end-to-end still needs a Docker/KVM host (CI).

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

bot_bottle/resources.py

@@ -0,0 +1,131 @@
+"""Locate build-time resources whether bot-bottle runs from a source
+checkout or an installed wheel.
+
+The gateway / infra / orchestrator images are built from a Docker (or Apple
+`container`) build context that must contain the `bot_bottle` package,
+`pyproject.toml`, and the root-level Dockerfiles as siblings. In a source
+checkout that context is simply the repo root, one level above the package.
+An installed wheel has no repo root: the same root-level files are shipped
+inside the package under ``bot_bottle/_resources/`` (see ``setup.py``), and a
+repo-root-shaped build context is staged on demand into the app-data dir.
+
+``build_root()`` is the single source of truth — it returns a directory laid
+out like a repo root (has ``bot_bottle/``, ``pyproject.toml``, the
+Dockerfiles, ``nix/``, ``scripts/``). Every caller that needs a build
+context, a Dockerfile path, the nix netpool module, or the netpool script
+derives from it, so checkout and wheel installs share one downstream path.
+"""
+
+from __future__ import annotations
+
+import shutil
+from pathlib import Path
+
+from .paths import bot_bottle_root
+
+_PKG = Path(__file__).resolve().parent          # …/bot_bottle
+_CHECKOUT_ROOT = _PKG.parent                     # repo root in a checkout
+_BUNDLED = _PKG / "_resources"                   # wheel-shipped copies
+
+# Root-level files bundled into the wheel under ``_resources/`` (paths are
+# relative to the checkout root, and preserved verbatim under ``_resources/``
+# and in the staged build root). ``setup.py`` copies exactly this set; keep
+# the two lists in sync (``test_resources`` guards that every entry exists).
+BUNDLED_RESOURCES: tuple[str, ...] = (
+    "pyproject.toml",
+    "Dockerfile.gateway",
+    "Dockerfile.orchestrator",
+    "Dockerfile.orchestrator.fc",
+    "nix/firecracker-netpool.nix",
+    "scripts/firecracker-netpool.sh",
+)
+
+# Present at a checkout root, never in a bare installed package — the cheap
+# tell for which layout we're in.
+_CHECKOUT_MARKER = "Dockerfile.gateway"
+
+
+class ResourceError(RuntimeError):
+    """Build resources are missing from the install (corrupt/partial wheel)."""
+
+
+def is_source_checkout() -> bool:
+    """True when running from a source tree (the root Dockerfiles sit beside
+    the package); False from an installed wheel."""
+    return (_CHECKOUT_ROOT / _CHECKOUT_MARKER).is_file()
+
+
+def build_root() -> Path:
+    """A directory shaped like a repo root: ``bot_bottle/``, ``pyproject.toml``,
+    the root Dockerfiles, ``nix/``, and ``scripts/``.
+
+    A checkout returns the repo root itself (no copying). An installed wheel
+    returns a staged copy under the app-data dir, materialized once and reused
+    (keyed by distribution version)."""
+    if is_source_checkout():
+        return _CHECKOUT_ROOT
+    return _stage_build_root()
+
+
+def dockerfile(name: str) -> Path:
+    """Absolute path to a root-level Dockerfile, e.g. ``Dockerfile.gateway``."""
+    return build_root() / name
+
+
+def nix_netpool_module() -> Path:
+    """Absolute path to the firecracker netpool NixOS module."""
+    return build_root() / "nix" / "firecracker-netpool.nix"
+
+
+def netpool_script() -> Path:
+    """Absolute path to the firecracker netpool bring-up script."""
+    return build_root() / "scripts" / "firecracker-netpool.sh"
+
+
+def _dist_version() -> str:
+    """Installed distribution version, for keying the staged build root. Falls
+    back to ``dev`` when metadata is unavailable (e.g. running from a tree)."""
+    try:
+        from importlib.metadata import PackageNotFoundError, version
+        try:
+            return version("bot-bottle")
+        except PackageNotFoundError:
+            return "dev"
+    except Exception:  # pragma: no cover - importlib.metadata is always present
+        return "dev"
+
+
+def _stage_build_root() -> Path:
+    """Materialize a repo-root-shaped build context from the installed wheel's
+    bundled resources. Idempotent and cached on disk by version."""
+    if not _BUNDLED.is_dir():
+        raise ResourceError(
+            "bot-bottle build resources are missing from this install "
+            f"(expected {_BUNDLED}). Reinstall the package."
+        )
+    dest = bot_bottle_root() / "build-root" / _dist_version()
+    if (dest / ".complete").is_file():
+        return dest
+
+    staging = dest.with_name(dest.name + ".staging")
+    shutil.rmtree(staging, ignore_errors=True)
+    staging.mkdir(parents=True, exist_ok=True)
+
+    # The package itself, minus caches and the bundled-resource copies, so the
+    # staged ``bot_bottle/`` matches a checkout's (keeps the firecracker
+    # infra-artifact content hash stable across checkout and wheel installs).
+    shutil.copytree(
+        _PKG,
+        staging / "bot_bottle",
+        ignore=shutil.ignore_patterns("__pycache__", "*.pyc", "_resources"),
+    )
+    # The bundled root files, restored to their checkout-relative layout.
+    for rel in BUNDLED_RESOURCES:
+        dst = staging / rel
+        dst.parent.mkdir(parents=True, exist_ok=True)
+        shutil.copy2(_BUNDLED / rel, dst)
+
+    shutil.rmtree(dest, ignore_errors=True)
+    staging.rename(dest)
+    (dest / ".complete").write_text("")
+    return dest