[Feature]: Add first-class uv tool install support

[Drswith]

Problem or opportunity

Quantex can currently model managed installs for bun, npm, brew, cargo, and winget, but uv tool installs are not represented as a first-class managed installer. Python-based agent CLIs that recommend uv tool install ... are therefore modeled as unmanaged command hints or one-off self-update commands instead of participating in the shared managed lifecycle.

Local intake examples:

• src/agents/definitions/openhands.ts exposes binaryInstall('uv tool install openhands --python 3.12') and a uv tool upgrade ... self-update command.
• src/agents/definitions/vibe.ts exposes binaryInstall('uv tool install mistral-vibe').
• src/agents/definitions/kimi.ts exposes uv tool upgrade kimi-cli --no-cache as a self-update command.
• ManagedInstallType currently excludes uv, so capabilities, doctor, state, schema, grouped updates, and install guidance cannot treat uv-installed agents as managed installs.

That leaves uv-supported agents less agent-friendly than npm/cargo/brew agents even when upstream documents uv as the preferred installation path.

Desired outcome

Users and agents should be able to install, inspect, update, and uninstall supported uv-distributed agent CLIs through Quantex using a first-class uv managed install method when upstream documentation verifies uv tool install as a supported distribution channel.

Expected direction:

• Add uv as a managed install type and package metadata target where appropriate.
• Add a catalog helper such as uvToolInstall(...) for agent definitions, including support for package install args like --python 3.12 and --no-cache when needed.
• Add uv availability to qtx capabilities and qtx doctor output.
• Add a uv package-manager provider for uv tool install, uv tool upgrade, uv tool uninstall, and installed-version inspection where reliable.
• Update structured schema/spec coverage so uv is part of the stable machine-readable contract.
• Migrate verified uv-based agent definitions, starting with OpenHands and Mistral Vibe if their uv install paths remain upstream-supported.

Scope and non-goals

In scope:

• Modeling uv tool installs as managed installer lifecycle operations.
• Cross-platform command planning for Windows, macOS, and Linux.
• Detection of an available uv command.
• State recording, command rendering, grouped update behavior, structured output, and validation updates needed for the new install type.
• OpenSpec coverage for the behavior contract before implementation.

Non-goals:

• Treating uv as a full Python environment manager inside Quantex.
• Managing virtualenv creation, Python version installation policy, pyenv/asdf policy, or arbitrary uv run workflows.
• Replacing separate pip support; pip and uv should remain distinct installer surfaces because they have different lifecycle commands and state behavior.
• Publishing Quantex itself through Python packaging.
• Expanding Quantex into a workflow orchestration platform.

Linked discussion or prior context

Related issue: #238 tracks first-class pip install support. This issue should stay separate because uv is not pip-compatible lifecycle plumbing; it uses uv tool ... commands and has different state/update semantics.

Local context observed during intake:

• src/agents/types.ts currently defines ManagedInstallType = 'bun' | 'npm' | 'brew' | 'cargo' | 'winget'.
• src/agents/definitions/openhands.ts, src/agents/definitions/vibe.ts, and src/agents/definitions/kimi.ts already reference uv commands.
• openspec/specs/agent-catalog/spec.md already mentions uv-based Kimi self-update behavior.

Which durable artifacts should this likely create or update?

• OpenSpec

Done when

• An OpenSpec change captures the uv managed-install contract before implementation starts.
• uv is represented in agent package metadata, managed install types, install method helpers, installer capabilities, command rendering, grouped update ordering, and structured schema where applicable.
• qtx capabilities and qtx doctor report uv availability consistently with other managed installers.
• Install, update, uninstall, inspect/resolve guidance, and recorded install state handle uv-installed agents consistently with the existing lifecycle model.
• Verified uv-distributed agent definitions are migrated from unmanaged command hints to the new managed uv method where upstream docs support it.
• Tests cover the new managed installer behavior, structured output/schema changes, and representative catalog usage with install args.
• User-facing docs/specs are updated if the observable install surface changes.

Guardrails

• I understand this issue should promote durable outcomes into repo-native docs instead of adding new ad hoc root markdown files.
• I understand this issue should stay within Quantex's lifecycle CLI scope unless an explicit decision changes that scope.