feat(packaging): split into slim Stainless-managed client + hand-authored ADK overlay

Inverts the package-ownership direction so Stainless owns what it natively
generates and the hand-authored ADK overlay lives in its own subdir.

Layout changes:
- src/agentex/lib/ → adk/src/agentex/lib/  (`git mv`)
- Root pyproject.toml: renamed agentex-sdk → agentex-sdk-client; dropped
  the 38 ADK deps; reverted requires-python to >= 3.11 (slim has no
  3.12-only imports); removed the `agentex` CLI entry point.
- New adk/pyproject.toml: name = agentex-sdk; depends on agentex-sdk-client
  + 31 ADK deps; requires-python >= 3.12; ships only agentex/lib/*; owns
  the `agentex` CLI entry point.

Net effect for consumers:
- pip install agentex-sdk        → same as today (heavy install)
- pip install agentex-sdk-client → NEW slim option (6 deps, REST client only)

Non-breaking. agentex-sdk now depends on agentex-sdk-client, so existing
consumers transitively get the slim client deps without any code change.

Why invert: the previous design (slim sibling under client/, heavy at root)
required hand-modifying Stainless's emitted root pyproject.toml — risky
under codegen 3-way merge. With the inversion:
- Root pyproject.toml is 100% Stainless-owned (no manual edits to fight)
- ADK overlay is self-contained in adk/ — preserved via `keep_files`
- The future repo split (Option B in AGX1-292) becomes trivially
  `mv adk/ ../scale-agentex-adk/`

Required Stainless dashboard work before this can ship:
- Set targets.python.options.package_name = "agentex-sdk-client"
- Reduce dashboard's dep list to the 6 bare-client deps
- Add `adk/**` to keep_files

Required PyPI work:
- Claim agentex-sdk-client package name; add token to repo secrets
- agentex-sdk publishing token moves to publish from adk/ (or stays in
  same repo, just sourced from adk/)

Verified locally with Python 3.13:
- Both wheels build cleanly (slim: 154 files, 6 deps; heavy: agentex/lib/
  only, 32 deps including agentex-sdk-client)
- Dual-install: no file conflicts; all imports resolve from both packages

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: max-parke-scale

adk/README.md

@@ -0,0 +1,110 @@
+[project]
+# Hand-authored ADK overlay for agentex. This package contributes only
+# `agentex/lib/*` to the agentex.* namespace; the REST client surface
+# (agentex/{__init__.py, _*.py, types/, resources/}) ships from the slim
+# sibling package `agentex-sdk-client` which is pinned as a runtime dep.
+#
+# This entire `adk/` directory must be preserved across Stainless codegen
+# via `keep_files: ["adk/**"]` in the Stainless dashboard config.
+name = "agentex-sdk"
+version = "0.11.4"
+description = "Agent Development Kit (ADK) overlay for the Agentex API — FastACP server, Temporal workflows, LLM provider integrations, observability"
+license = "Apache-2.0"
+authors = [
+  { name = "Agentex", email = "roxanne.farhad@scale.com" },
+]
+readme = "README.md"
+
+dependencies = [
+    "agentex-sdk-client",
+    # CLI surface (agentex.lib.cli.*, agentex.lib.sdk.config.*)
+    "typer>=0.16,<0.17",
+    "questionary>=2.0.1,<3",
+    "rich>=13.9.2,<14",
+    "yaspin>=3.1.0",
+    "pyyaml>=6.0.2,<7",
+    "python-on-whales>=0.73.0,<0.74",
+    "kubernetes>=25.0.0,<36.0.0",
+    "jsonref>=1.1.0,<2",
+    "jsonschema>=4.23.0,<5",
+    "jinja2>=3.1.3,<4",
+    "watchfiles>=0.24.0,<1.0",
+    # ACP server (FastAPI app surface)
+    "fastapi>=0.115.0",
+    "starlette>=0.49.1",
+    "uvicorn>=0.31.1",
+    "aiohttp>=3.10.10,<4",
+    # Temporal workflows
+    "temporalio>=1.26.0,<2",
+    "cloudpickle>=3.1.1",
+    # Async streaming infra
+    "redis>=5.2.0,<8",
+    # LLM provider integrations
+    "litellm>=1.83.7,<2",
+    "openai-agents==0.14.1",
+    "openai>=2.2,<3", # Required by openai-agents; litellm now supports openai 2.x (issue #13711 resolved: https://github.com/BerriAI/litellm/issues/13711)
+    "claude-agent-sdk>=0.1.0",
+    "pydantic-ai-slim>=1.0,<2",
+    "langgraph-checkpoint>=2.0.0",
+    "scale-gp>=0.1.0a59",
+    "scale-gp-beta>=0.2.0",
+    "mcp>=1.4.1",
+    # Observability
+    "ddtrace>=3.13.0",
+    "opentelemetry-api>=1.20.0",
+    "opentelemetry-sdk>=1.20.0",
+    "json_log_formatter>=1.1.1",
+]
+
+# agentex/lib/* uses `from typing import override` (3.12+) in 19 files.
+# The slim agentex-sdk-client keeps 3.11 support.
+requires-python = ">= 3.12,<4"
+classifiers = [
+  "Typing :: Typed",
+  "Intended Audience :: Developers",
+  "Programming Language :: Python :: 3.12",
+  "Programming Language :: Python :: 3.13",
+  "Programming Language :: Python :: 3.14",
+  "Operating System :: OS Independent",
+  "Topic :: Software Development :: Libraries :: Python Modules",
+  "License :: OSI Approved :: Apache Software License",
+]
+
+[project.urls]
+Homepage = "https://github.com/scaleapi/scale-agentex-python"
+Repository = "https://github.com/scaleapi/scale-agentex-python"
+
+[project.scripts]
+agentex = "agentex.lib.cli.commands.main:app"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+# Ship only agentex/lib/*. The rest of agentex.* (the Stainless-generated
+# client) ships from the sibling agentex-sdk-client package, which this
+# package pins as a runtime dep.
+[tool.hatch.build.targets.wheel]
+only-include = ["src/agentex/lib"]
+sources = ["src"]
+# Don't ship internal test files in the wheel; CLI Jinja templates
+# (test_agent.py.j2 etc.) are preserved because they don't match these globs.
+exclude = [
+  "src/agentex/lib/**/tests/**",
+  "src/agentex/lib/**/test_*.py",
+  "src/agentex/lib/**/conftest.py",
+  "src/agentex/lib/**/pytest.ini",
+]
+
+[tool.hatch.build.targets.sdist]
+include = [
+  "/pyproject.toml",
+  "/README.md",
+  "/src/agentex/lib/**",
+]
+exclude = [
+  "/src/agentex/lib/**/tests/**",
+  "/src/agentex/lib/**/test_*.py",
+  "/src/agentex/lib/**/conftest.py",
+  "/src/agentex/lib/**/pytest.ini",
+]