feat(errors): add ACR permission denied error handling and suggestions

[therealjohn]

feat(cspell): update cspell.yaml with new project-specific terms
test: enhance tests for ACR permission guidance and error classification

Fixes #8483

[Copilot]

Pull request overview

This PR improves Azure AI Agents container publish error handling by distinguishing ACR RBAC/auth failures from private-network ACR failures and providing targeted remediation guidance.

Changes:

• Adds acr_permission_denied structured error classification and user-facing ACR role assignment guidance.
• Tightens private ACR network classification to avoid misclassifying RBAC failures.
• Expands tests for ACR permission/network classification and updates extension spell-check terms.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
cli/azd/extensions/azure.ai.agents/internal/project/service_target_agent.go	Adds ACR permission classifier, remediation suggestion, shared ACR context signals, and regex parsing for ARM errors.
cli/azd/extensions/azure.ai.agents/internal/project/service_target_agent_test.go	Adds/updates tests for permission guidance, dynamic substitution, placeholder fallback, and non-ACR negative cases.
cli/azd/extensions/azure.ai.agents/internal/exterrors/codes.go	Registers the new acr_permission_denied error code.
cli/azd/extensions/azure.ai.agents/cspell.yaml	Adds project-specific terms used by the new error matching and tests.

[trangevi]

/check-enforcer override