[Epic] Keep dependencies, tools, APIs, and client platforms compatible

## Problem statement

Azure MCP, CLIs, SDKs, models, operating systems, architectures, clients, and service APIs evolve independently. Compatibility drift can break supported behavior without a product-code change.

## Outcome

Supported dependencies and platform contracts remain current, tested, and migrated before enforcement dates.

## Goals

- Track supported dependency and platform lifecycles
- Plan migrations for deprecations and breaking changes
- Validate compatibility across supported clients and environments
- Complete critical updates within defined service levels

## Non-goals

- Supporting deprecated platforms indefinitely
- Tracking net-new integrations as maintenance

## Success criteria

- [ ] Supported-version policy and ownership are documented
- [ ] Breaking changes have migration plans before enforcement
- [ ] Compatibility checks cover critical contracts

## Dependencies

Upstream roadmaps, Dependabot, Azure MCP, CLI and SDK owners, and client teams.

Start by defining the supported-version policy and ownership described in the success criteria. Review upstream roadmaps, Dependabot, Azure MCP, CLI and SDK owners, and client teams to identify lifecycle risks and critical compatibility contracts. Done means the policy is documented, breaking changes have migration plans, and compatibility checks cover critical contracts.

Written by the indexing model from the issue text.