Pin LiteLLM for install stability (#263)

## Summary

Prepare v0.5.3 from the latest `main`, including sandbox provider/tool
work, sandbox follow-up fixes/improvements, agent swarm lifecycle
stabilization, and a fix for fresh `uv tool install ouro-ai` failures
caused by dependency resolution selecting `litellm==1.93.0` in
environments where its build path requires Rust/maturin.

## Scope

- Goals:
- Include sandbox provider/tool support already merged to `main` (#259).
- Include sandbox follow-ups from latest `main`: helper lazy start,
BoxLite profile options, latest Smol SDK support, and persistent Smol
machine reuse (#264, #265, #267, #268).
  - Include agent swarm task lifecycle stabilization (#266).
  - Pin runtime `litellm` to the validated `1.87.0` release.
  - Bump package metadata to `0.5.3` for a patch release.
- Document included main updates and install-stability changes in
`CHANGELOG.md`.
- Non-goals:
  - Upgrade LiteLLM.
- Change behavior beyond the already-merged main PRs plus packaging
metadata.

## Invariants (Must Not Regress)

- [x] Package name remains `ouro-ai`.
- [x] `pyproject.toml` and `uv.lock` package versions match.
- [x] Runtime package metadata requires `litellm==1.87.0`.
- [x] Sandbox packages are included in the wheel.
- [x] Existing tests/type/import-lint gates continue to pass.

## Acceptance Criteria

- [x] v0.5.3 is based on latest `origin/main` (`b4f45e2`, #268).
- [x] Fresh installs of the next release do not resolve
`litellm==1.93.0`.
- [x] Built wheel metadata contains `Requires-Dist: litellm==1.87.0`.
- [x] Built wheel includes sandbox core/capabilities/tool modules.
- [x] Changelog includes v0.5.3 sandbox, swarm, sandbox follow-up, and
install-stability notes.

## Test Plan

- [x] `./scripts/dev.sh check`
- [x] `./scripts/dev.sh build`
- [x] Inspected built wheel `METADATA` for `Version: 0.5.3` and
`Requires-Dist: litellm==1.87.0`
- [x] Inspected built wheel contents for sandbox modules:
  - `ouro/core/sandbox/__init__.py`
  - `ouro/capabilities/sandbox/manager.py`
  - `ouro/capabilities/sandbox/adapters/boxlite.py`
  - `ouro/capabilities/sandbox/adapters/smolvm.py`
  - `ouro/capabilities/tools/builtins/sandbox.py`

## Smoke Run (Real CLI)

- [ ] Not run; release prep/packaging metadata update plus
already-tested merged main PRs.

## Adversarial Review (Answer Briefly)

- What existing behavior could this break? Only users relying on a newer
LiteLLM than 1.87.0 through ouro dependency graph; intentional to
restore install stability.
- Worst-case input/output size? No new runtime path in this PR beyond
already-merged main functionality.
- Any secrets/logging risks? No new changes here; sandbox feature
docs/config were merged in main.
- Any async/blocking I/O added on hot paths? No new changes in this
release prep PR.
- What error message does the user see on failure? No new user-facing
failure path from release prep.

## Docs / Compatibility

- [x] Updated `CHANGELOG.md`.
- [x] Sandbox docs already included from main.
- [x] No secrets committed; no generated artifacts.

🤖 Generated with ouro (https://github.com/ouro-ai-labs/ouro)

Co-authored-by: ouro <197364660+ouro-ai-lab@users.noreply.github.com>

Author: luohaha

CHANGELOG.md

@@ -7,6 +7,21 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.3] - 2026-07-26
+
+### Added
+
+- **Sandbox providers and tools**: added configurable sandbox execution support, adapters for BoxLite and SmolVM, sandbox-aware file/shell tools, `--sandbox` CLI wiring, BoxLite profile options, latest Smol SDK support, persistent Smol machine reuse, and sandbox documentation (#259, #265, #267, #268).
+
+### Changed
+
+- **Agent swarm stability**: stabilized agent swarm task lifecycle handling (#266).
+
+### Fixed
+
+- **Sandbox helper startup**: fixed sandbox helper lazy start behavior (#264).
+- **Install stability**: pin runtime `litellm` to the validated `1.87.0` release so fresh installs do not resolve to newer LiteLLM builds that may require Rust/maturin builds in some environments.
+
 ## [0.5.2] - 2026-07-26
 
 ### Added

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "ouro-ai"
-version = "0.5.2"
+version = "0.5.3"
 description = "General AI Agent System"
 readme = "README.md"
 requires-python = ">=3.12"
@@ -33,7 +33,7 @@ dependencies = [
     "trafilatura>=2.0.0",
     "lxml>=5.0.0",
     "aiofiles>=24.1.0",
-    "litellm>=1.87.0,<2.0",
+    "litellm==1.87.0",
     "PyYAML>=6.0",
     "tiktoken>=0.5.0",
     "tenacity>=8.2.0",