Merged PR 2242: Refactor: New Appeal flow structural cleanup (Slices 1–8, no behaviour change)

## Summary

This PR merges the completed new-appeal refactor stream (Slices 1–8) into SIPS-Development.

This refactor was executed in controlled slices with regression validation at each step.

## Scope

Structural and readability improvements only:
- XML/form derivation extraction
- payload and file helper extraction
- side-effect facade introduction
- BuildSection and BuildCheckSection decomposition
- BuildCheckRow formatter map refactor
- nested prop boundary cleanup
- start-flow cleanup (CreateCase / AboutYou)

## Behaviour

No intended behavioural changes.

The following were explicitly preserved:
- S78 journey behaviour
- payload shapes and field names/ids
- HASCAS mapping logic
- appellant/agent branching
- validation rules and messages
- redirect/query parameters (`lpa`, `apt`, `id`)
- navigation and side-effect sequencing
- EN/CY output parity

## Validation

Full regression has been performed on:
- start flow (CreateCase / AboutYou)
- save and resume flows
- file upload handling
- check answers rendering
- submit/finalisation sequence
- confirmation flow
- CRM insertion path
- EN/CY parity

Additional checks:
- docsOffline branch behaviour
- completion and partial-save email paths
- negative-path validation scenarios
- lint (warnings baseline unchanged)

## Risk

Low:
- changes are structural only
- no business logic changes
- no contract changes

## Rollback

Safe rollback via reverting this merge commit.

## Notes

This refactor reduces coupling and prepares the new-appeal flow for future appeal-type expansion.

Related work items: #22570, #22576, #22577, #22583, #22586, #22587, #22588, #22590

.gitignore

@@ -52,11 +52,7 @@ pages/holding-min.html
 pages/holding.html
 
 # Cline / AI-assistant governance artifacts (keep local-only)
-.clinerules
-.clinerules/
-CONTRIBUTING_AI.md
-GUARDRAILS.md
+
 ai-prompts/
-workflows/
-AI_CONTEXT.md
+
 pages/baracuda.min.html