PLAN: prepare shared extraction (duplicate helpers → src/shared)

- defined scope for identifying duplicate helpers
- no code or structure changes
- sets up next BUILD PR with exact file targets

next:
- BUILD_PR_SHARED_EXTRACTION_01_MOVE_HELPERS

Author: DavidQ

docs/dev/COMMIT_COMMENT.txt

@@ -1,7 +1,8 @@
-APPLY: finalize repo structure normalization (03) remove legacy engine directory
+PLAN: prepare shared extraction (duplicate helpers → src/shared)
 
-- removed root-level engine/ directory
-- src/engine/ is now the only engine location
+- defined scope for identifying duplicate helpers
+- no code or structure changes
+- sets up next BUILD PR with exact file targets
 
 next:
-- shared extraction
+- BUILD_PR_SHARED_EXTRACTION_01_MOVE_HELPERS

docs/dev/reports/change_summary.txt

@@ -1 +1,4 @@
-removed legacy engine directory
+CHANGE SUMMARY
+
+- preparing shared extraction plan
+- no code changes

docs/dev/reports/validation_checklist.txt

@@ -1,2 +1,5 @@
-[x] engine removed
-[x] src/engine intact
+VALIDATION CHECKLIST
+
+[x] no code changes
+[x] no file moves
+[x] ready for BUILD with exact targets

docs/pr/PLAN_PR_SHARED_EXTRACTION_PREP.md

@@ -0,0 +1,26 @@
+# PLAN PR — Shared Extraction Preparation
+
+## Purpose
+Prepare exact, surgical extraction of duplicated helpers into `src/shared/`.
+
+## Scope
+- Identify duplicate helpers across:
+  - samples/
+  - tools/
+  - src/
+- Classify into target buckets:
+  - numbers/
+  - objects/
+  - arrays/
+  - strings/
+  - state/
+- Define exact move targets (no execution yet)
+
+## Constraints
+- No code changes
+- No file moves yet
+- No refactors
+- No API changes
+
+## Output
+- exact file list for next BUILD PR