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

.clinerules/templates/bugfix.md

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+# Bugfix Workflow
+
+1. Clarify the bug symptoms and expected behavior.
+2. Inspect the relevant files and execution path.
+3. Identify the most likely root cause.
+4. Implement the smallest safe fix.
+5. Check for:
+   - side effects
+   - regression risk
+   - validation gaps
+   - missing error handling
+6. Summarize:
+   - root cause
+   - fix
+   - preventive improvements worth noting

.clinerules/templates/code-review.md

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+# Code Review Workflow
+
+Review the relevant code or changes for:
+- correctness
+- edge cases
+- data integrity
+- security concerns
+- performance concerns
+- maintainability
+- readability
+- consistency with repo conventions
+
+Return:
+1. key findings
+2. impact / severity where useful
+3. suggested improvements
+4. strengths worth preserving

.clinerules/templates/database-migration.md

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+# Database Migration Workflow
+
+1. Understand the desired schema or data change.
+2. Inspect current data model, queries, and dependent code.
+3. Identify:
+   - forward migration steps
+   - backward compatibility concerns
+   - rollback considerations
+4. Implement or propose the minimal safe migration path.
+5. Review for:
+   - data integrity
+   - ordering issues
+   - application compatibility
+   - deployment timing risk
+6. Summarize:
+   - schema/data changes
+   - impacted code paths
+   - rollout / rollback notes

.clinerules/templates/debugging.md

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+# Debugging Workflow
+
+1. Capture the symptom, error, or incorrect behavior.
+2. Inspect the relevant path and recent changes.
+3. Form the most likely hypotheses.
+4. Narrow the cause using the smallest practical evidence checks.
+5. Propose or implement the minimal safe fix.
+6. Review for:
+   - hidden assumptions
+   - unhandled states
+   - logging or observability gaps
+   - regression risk
+7. Summarize:
+   - symptom
+   - cause
+   - fix
+   - prevention ideas

.clinerules/templates/documentation-update.md

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+# Documentation Update Workflow
+
+1. Identify what changed in the code or workflow.
+2. Inspect the affected docs and support files.
+3. Update only the relevant sections.
+4. Keep the docs concise, factual, and current.
+5. Summarize:
+   - what changed
+   - which docs were updated
+   - anything still uncertain

.clinerules/templates/feature-implementation.md

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+# Feature Implementation Workflow
+
+1. Understand the requirement and desired outcome.
+2. Inspect the relevant files, patterns, and data flows.
+3. Propose a short implementation plan for non-trivial work.
+4. Implement the smallest maintainable change that satisfies the requirement.
+5. Review for:
+   - correctness
+   - edge cases
+   - error handling
+   - compatibility with existing behavior
+   - maintainability
+6. Summarize:
+   - what changed
+   - why
+   - any follow-up considerations

.clinerules/templates/planning.md

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+# Planning Workflow
+
+1. Clarify the objective.
+2. Inspect the relevant code areas and constraints.
+3. Identify implementation options.
+4. Compare trade-offs.
+5. Recommend the most practical path.
+6. Return:
+   - objective summary
+   - proposed plan
+   - risks
+   - dependencies
+   - suggested execution order

.clinerules/templates/pr-review.md

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+# PR Review Workflow
+
+Review the pull request or change set for:
+- correctness
+- scope discipline
+- regression risk
+- compatibility impact
+- tests or validation gaps
+- security and performance concerns
+- maintainability
+
+Return:
+1. summary of change intent
+2. key risks
+3. requested changes
+4. optional improvements

.clinerules/templates/refactor.md

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+# Refactor Workflow
+
+1. Understand the current behavior that must be preserved.
+2. Inspect the relevant modules and dependencies.
+3. Identify safe refactor boundaries.
+4. Propose a scoped plan.
+5. Refactor incrementally.
+6. Review for:
+   - preserved behavior
+   - reduced complexity
+   - improved readability
+   - regression risk
+7. Summarize:
+   - what was simplified
+   - what was preserved
+   - remaining debt

.clinerules/templates/release-readiness.md

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+# Release Readiness Workflow
+
+1. Review the scope of changes.
+2. Check:
+   - build readiness
+   - environment assumptions
+   - configuration changes
+   - database implications
+   - CI/CD impact
+   - rollback expectations
+3. Identify release risks and missing checks.
+4. Summarize:
+   - release blockers
+   - risks
+   - final recommended checks