APPLY: finalize repo structure normalization (03) remove legacy engine directory

- removed root-level engine/ directory
- src/engine/ is now the only engine location

next:
- shared extraction

Author: DavidQ

docs/dev/CODEX_COMMANDS.md

@@ -1,2 +1 @@
-# No Codex command in this APPLY bundle
-# Code is already reported complete and validated.
+# no codex

docs/dev/COMMIT_COMMENT.txt

@@ -1,11 +1,7 @@
-APPLY: accept repo structure normalization (02) import switch
+APPLY: finalize repo structure normalization (03) remove legacy engine directory
 
-- updated imports from engine/ to src/engine/
-- confirmed 532 files updated
-- confirmed 0 remaining legacy engine import specifiers
-- no logic changes beyond import path normalization
-- original engine/ retained for rollback safety
+- removed root-level engine/ directory
+- src/engine/ is now the only engine location
 
 next:
-- validate runtime stability
-- remove legacy engine/ directory in final cutover PR
+- shared extraction

docs/dev/reports/change_summary.txt

@@ -1,6 +1 @@
-CHANGE SUMMARY
-
-- accepted import normalization from `engine/...` to `src/engine/...`
-- confirmed 532 files updated
-- confirmed 0 remaining legacy engine import specifiers
-- confirmed original `engine/` directory remains unchanged
+removed legacy engine directory

docs/dev/reports/file_tree.txt

@@ -1,12 +1,2 @@
-FILE TREE
-
-docs/
-├── pr/
-│   └── APPLY_PR_REPO_STRUCTURE_NORMALIZATION_02_IMPORT_SWITCH.md
-└── dev/
-    ├── commit_comment.txt
-    ├── codex_commands.md
-    └── reports/
-        ├── change_summary.txt
-        ├── file_tree.txt
-        └── validation_checklist.txt
+src/engine/
+(engine removed)

docs/dev/reports/validation_checklist.txt

@@ -1,9 +1,2 @@
-VALIDATION CHECKLIST
-
-[x] Import/export/require specifiers updated to `src/engine/...`
-[x] 532 files updated
-[x] 0 remaining legacy `engine/...` specifiers in import/export/require statements
-[x] No logic changes beyond import string replacement
-[x] No deletions performed
-[x] Original `engine/` directory remains unchanged
-[x] Ready for final cutover PR
+[x] engine removed
+[x] src/engine intact

docs/pr/APPLY_PR_REPO_STRUCTURE_NORMALIZATION_03_REMOVE_OLD_ENGINE.md

@@ -0,0 +1,4 @@
+# APPLY PR — Repo Structure Normalization (03)
+
+Remove legacy engine/ directory.
+src/engine/ is now authoritative.

docs/pr/BUILD_PR_REPO_STRUCTURE_NORMALIZATION_03_REMOVE_OLD_ENGINE.md

@@ -0,0 +1,28 @@
+# BUILD PR — Repo Structure Normalization (03) Remove Legacy `engine/` Directory
+
+## Scope
+Remove the old root-level `engine/` directory now that:
+- `src/engine/` exists as a verified 1:1 mirror
+- imports have been switched to `src/engine/...`
+- no legacy `engine/...` import/export/require statements remain
+
+## Constraints
+- DO NOT scan repo broadly
+- ONLY verify and remove the root-level `engine/` directory
+- NO engine API changes
+- NO new source files
+- NO import changes in this PR
+
+## Targets
+- Remove directory: `engine/`
+
+## Non-Goals
+- No refactors
+- No logic edits
+- No changes under `src/engine/`
+- No changes to docs beyond this PR bundle
+
+## Validation
+- `engine/` no longer exists
+- `src/engine/` remains intact
+- app/runtime still resolves engine imports through `src/engine/...`