Support project-local deployment configuration

[dosu-oss-pool-10]

Problem

The CLI stores all configuration in a single user-level file (~/.config/dosu-cli/config.json). When working across multiple projects that each have their own MCP deployment, running dosu setup --deployment <id> overwrites the global active_account.target.deployment_id, so the last-configured deployment wins for all projects.

This means dosu audit --tasks ... always runs against the last-added deployment regardless of which project directory the user is in and regardless of what that project's MCP server is set to.

Expected Behavior

The CLI should support project-scoped deployment configuration so that running dosu audit (or other commands) in a given project directory automatically targets the correct deployment without manual overrides.

Suggested Approach

Introduce a layered config resolution that checks for a project-local config before falling back to the global user-level config. For example:

1. Project-local config file — e.g., .dosu/config.json in the project root (the .dosu/ directory already exists for audit artifacts like .dosu/audit.json). This file could store deployment_id, org_id, data_source_id, and api_key overrides scoped to that project.
2. dosu setup --deployment <id> --local — a flag to write the deployment binding to the project-local config instead of the global one.
3. Config resolution chain — commands like audit would check for .dosu/config.json first, then fall back to the global config.

As a simpler interim step, supporting --deployment or --data-source-id directly on the audit command would also help.

Context

Reported by a user managing multiple projects with separate deployments. Current workarounds are either passing --data-source-id explicitly on every audit run, or re-running dosu setup --deployment <id> before switching projects.

[unclesp1d3r]

This is even more complex given the the hooks call the CLI, so I can't safely have hooks in all of my relevant repos without it becoming problematic.