chore(examples): add claude-cli and claude-sdk targets to agent-skills-evals example

[christso]

Problem

The examples/features/agent-skills-evals/ example demonstrates multi-provider skill-trigger evals, but the targets file (.agentv/targets.yaml) only defines an echo provider. Users who want to test with claude-cli or claude-sdk must create their own targets, which adds friction.

The parent examples/features/.agentv/targets.yaml has a claude target (provider: claude), but:

• No explicit claude-cli target
• No claude-sdk target
• The README shows --target claude --targets ../.agentv/targets.yaml but doesn't document the setup

Proposed Fix

Add claude-cli and claude-sdk targets to examples/features/.agentv/targets.yaml:

  - name: claude-cli
    provider: claude-cli
    grader_target: gemini-flash
    log_format: json

  - name: claude-sdk
    provider: claude-sdk
    grader_target: gemini-flash
    log_format: json

Update the multi-provider example README to document running with both providers.

Blocked By

• fix(claude-sdk): workspace skills not discovered by Claude Agent SDK provider #876 (claude-sdk workspace skill discovery) — claude-sdk target will fail for skill-trigger evals until that issue is resolved

Acceptance Criteria

• examples/features/.agentv/targets.yaml includes claude-cli and claude-sdk targets
• README documents how to run with each provider
• Running agentv eval multi-provider-skill-trigger.EVAL.yaml --target claude-cli works out of the box