chore: main to dev downmerge

[Saswato-Microsoft]

Purpose

Updating dev branch with main to dev downmerge.

Does this introduce a breaking change?

• Yes
• No

Golden Path Validation

• I have tested the primary workflows (the "golden path") to ensure they function correctly without errors.

Deployment Validation

• I have validated the deployment process successfully and all services are running as expected with this change.

What to Check

Verify that the following are valid

• ...

Other Information

[Copilot]

Pull request overview

This PR downmerges main into dev, bringing along recent infrastructure, deployment-script, and documentation updates—most notably shifting the default Foundry chat model deployment from gpt-4.1-mini to gpt-5-mini and replacing hard-coded Fabric ontology source GUIDs with placeholders intended for runtime substitution.

Changes:

• Updated default GPT deployment model/version in Bicep + parameters, and reflected the new default model in docs/workflow summaries.
• Replaced Fabric ontology lakehouse itemId GUID references with PLACEHOLDER-LAKEHOUSE-ID and aligned the installer notebook’s replacement constants.
• Minor documentation/script tidy-ups (FAQ model name, PowerShell script trailing comment).

Reviewed changes

Copilot reviewed 39 out of 39 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
TRANSPARENCY_FAQ.md	Updates stated default Foundry IQ chat model to GPT-5-mini.
src/fabric/fabric_workspace/ontology/**.json	Replaces hard-coded lakehouse GUIDs with placeholder IDs for deployment-time replacement.
infra/scripts/utils/Get-FabricOntologyDefinition.ps1	Adds a trailing comment at script end.
infra/scripts/install_microsoft_iq_solution.py	Updates default chat/agent model strings to gpt-5-mini.
infra/main.parameters.json	Updates GPT model defaults (name/version) and removes default AI deployments location.
infra/main.bicep	Updates GPT defaults and metadata usage hints to gpt-5-mini and new version date.
infra/fabric/deploy/fabric_solution_installer.ipynb	Replaces hard-coded source workspace/lakehouse GUID constants with placeholders used for string replacement.
infra/deploy_foundry_role_assignment.bicep	Adds optional model.version wiring for deployments.
infra/deploy_ai_foundry.bicep	Adds optional model.version wiring for deployments.
docs/foundry/DeploymentGuideFoundry.md	Updates Foundry guide to the new default model.
docs/DeploymentGuide.md	Updates top-level deployment guide to the new default model (but needs version sync).
.github/workflows/azure-dev.yml	Updates workflow summary text to the new default model.