refactor: improve error handling and logging across multiple components

[Ayaz-Microsoft]

Purpose

Code quality standard findings fixes - improve error handling and logging across multiple components

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 addresses code-quality findings by tightening error handling/logging and reducing unused code across the deployment script, frontend UI, and backend API/services.

Changes:

• Backend: refactors several components to use readonly fields, improves stream disposal, and adds best-effort exception handling paths.
• Frontend: removes/neutralizes unused state/handlers and trims unused imports.
• Deployment tooling: adds documentation clarifying JSON-parse fallback behavior during Bicep params validation.

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
Deployment/validate_bicep_params.py	Clarifies fallback behavior when parameters JSON parsing fails.
App/frontend-app/src/pages/home/home.tsx	Avoids unused state variables (but leaves some dead state/update paths).
App/frontend-app/src/components/sidecarCopilot/sidecar.tsx	Removes unused chat type imports/fields (one unused import remains).
App/frontend-app/src/components/searchResult/old.tsx	Removes an unused import.
App/frontend-app/src/components/searchBox/searchBox.tsx	Removes unused UI imports and upload logic (leaves unused import/variables).
App/frontend-app/src/components/documentViewer/documentViewer.tsx	Avoids unused state value while still passing setter down.
App/frontend-app/src/components/chat/modelSwitch.tsx	Removes unused constants/imports.
App/frontend-app/src/components/chat/chatRoom.tsx	Removes unused imports/styles/demo code; simplifies state.
App/backend-api/Microsoft.GS.DPS/Storage/Documents/DocumentRepository.cs	Small refactor for end-of-day time filtering variable usage.
App/backend-api/Microsoft.GS.DPS/Storage/Components/BusinessTransactionRepository.cs	Changes specification casting behavior (now explicit cast).
App/backend-api/Microsoft.GS.DPS/Storage/AISearch/TagUpdater.cs	Adds CA1031 suppression for best-effort tag updates.
App/backend-api/Microsoft.GS.DPS/API/UserInterface/DataCacheManager.cs	Simplifies keyword consolidation loop logic.
App/backend-api/Microsoft.GS.DPS/API/KernelMemory/KernelMemory.cs	Improves resource disposal; adds CA1031 suppression for malformed keyword output handling.
App/backend-api/Microsoft.GS.DPS/API/ChatHost/ChatHost.cs	Refactors fields to readonly, updates prompt-path building, adds CA1031 suppression in top-level catch.
App/backend-api/Microsoft.GS.DPS.Host/Helpers/TelemetryHelper.cs	Adds CA1031 suppression; adjusts dependency tracking call signature/shape.
App/backend-api/Microsoft.GS.DPS.Host/API/UserInterface/UserInterface.cs	Marks static thumbnails dictionary as readonly.
App/backend-api/Microsoft.GS.DPS.Host/API/KernelMemory/KernelMemory.cs	Adds null-file guard and removes unused completion flag variable.

Comments suppressed due to low confidence (1)

App/frontend-app/src/components/searchBox/searchBox.tsx:27

• fileInputRef is declared but unused (and the upload input/button is commented out), which will trigger unused-variable linting. Either remove UploadButton/fileInputRef entirely or restore the upload UI so the ref is used.

const UploadButton = () => {
    const fileInputRef = useRef<HTMLInputElement>(null);

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[Copilot]

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

App/frontend-app/src/pages/home/home.tsx:446

• handleChatWithDocument no longer uses its document parameter. With the repo's ESLint rules, unused args should be prefixed with _ or removed to avoid @typescript-eslint/no-unused-vars warnings.

    function handleChatWithDocument(document: Document) {
        setShowCopilot(true);
        if (headerMenuTabsRef.current && showCopilot === false) {
            headerMenuTabsRef.current.scrollIntoView({ behavior: "smooth" });
        }
    }