feat: add security proxy score command for Advanced API Security (#692)

[saiflayouni]

Summary

• Adds apigeecli securityprofiles score command to fetch the risk assessment score for a specific API proxy from an Advanced API Security profile
• New GetProxyScore client function in internal/client/securityprofiles/ that calls computeEnvironmentScores with the proxy's score path filter automatically constructed from org/env/proxy
• Users no longer need to know the internal scorePath filter format; just supply --proxy <name> and get back the JSON score response
• The command is designed to be pipeline-friendly: --start-time/--end-time accept RFC3339 format for time-bounded assessment windows

Example usage:

apigeecli securityprofiles score \
  --org my-org --env prod \
  --name default --proxy my-api \
  --start-time 2024-01-01T00:00:00Z \
  --end-time 2024-01-31T23:59:59Z

Fixes #692

Test plan

• Run apigeecli securityprofiles score --org <org> --env <env> --name <profile> --proxy <proxy> against an org with Advanced API Security enabled
• Verify the response contains the expected score/severity data for the proxy
• Verify default time range (last 24 hours) is used when --start-time/--end-time are omitted

🤖 Generated with Claude Code

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