Merge remote-tracking branch 'origin/main' into pr/26177-CHARLIE-029-system-health-postgres-metrics-panel

# Conflicts:
#	docs_build/dev/reports/codex_changed_files.txt
#	docs_build/dev/reports/codex_review.diff

Author: ToolboxAid

docs_build/dev/ProjectInstructions/backlog/BACKLOG_MASTER.md

@@ -241,11 +241,16 @@ Current OWNER clarification:
 
 ### Team Delta
 
-- [ ] Delta - Shared JS consolidation
-- [ ] Delta - API client consolidation
-- [ ] Delta - Runtime performance audit
-- [ ] Delta - Engine test coverage improvements
-- [ ] Delta - Event system audit
+- [x] Delta - Shared JS consolidation
+  - Completion reference: PR_26175_DELTA_002_Shared_Runtime_Consolidation.
+- [x] Delta - API client consolidation
+  - Completed by PR_26175_DELTA_003_API_Client_Standardization.
+- [x] Delta - Runtime performance audit
+  - Completion reference: PR_26175_DELTA_001_Runtime_Performance_Optimization.
+- [x] Delta - Engine test coverage improvements
+  - Completed by PR_26175_DELTA_004_Runtime_Test_Expansion.
+- [x] Delta - Event system audit
+  - Completed by PR_26175_DELTA_005_Runtime_Technical_Debt_Cleanup.
 - [ ] Delta - Controls runtime framework audit
 - [ ] Delta - Object runtime framework audit
 - [ ] Delta - World runtime framework audit

docs_build/dev/reports/PR_26175_DELTA_001_Runtime_Performance_Optimization-branch-validation.md

@@ -0,0 +1,15 @@
+# PR_26175_DELTA_001 Branch Validation
+
+| Gate | Status | Evidence |
+| --- | --- | --- |
+| Current branch before work | PASS | `main` |
+| Worktree before work | PASS | Clean |
+| Local/origin sync before work | PASS | `0 0` after `git pull --ff-only` |
+| Team ownership | PASS | Team Delta owns Runtime, Performance, and Runtime test coverage. |
+| Work branch | PASS | `PR_26175_DELTA_001_Runtime_Performance_Optimization` |
+| Previous Delta PR closed | PASS | No active Delta PR was present before PR_001. |
+| Scope boundary | PASS | Runtime tick-loop optimization, focused test, backlog/report artifacts only. |
+
+## Instruction Reads
+
+PASS - All files under `docs_build/dev/ProjectInstructions/` were read before implementation.

docs_build/dev/reports/PR_26175_DELTA_001_Runtime_Performance_Optimization-manual-validation-notes.md

@@ -0,0 +1,9 @@
+# PR_26175_DELTA_001 Manual Validation Notes
+
+- Confirmed Team Delta ownership covers Runtime, Performance, and Runtime test coverage.
+- Confirmed the optimization is limited to fixed-step runtime tick advancement.
+- Confirmed `advanceRuntimeTick(...)` now reuses the existing `deltaSeconds` value when present.
+- Confirmed legacy tick objects without `deltaSeconds` still advance successfully.
+- Confirmed no browser-owned data, API contract, UI, or tool state changes were introduced.
+- Confirmed backlog completion reference was added for `Delta - Runtime performance audit`.
+- Confirmed source branch disposition should remain `retained`.

docs_build/dev/reports/PR_26175_DELTA_001_Runtime_Performance_Optimization-requirement-checklist.md

@@ -0,0 +1,19 @@
+# PR_26175_DELTA_001 Requirement Checklist
+
+| Requirement | Status | Notes |
+| --- | --- | --- |
+| Team Delta ownership only | PASS | Runtime, Performance, and Runtime test coverage are Delta-owned. |
+| One PR purpose | PASS | Fixed-step tick-loop performance optimization only. |
+| Preserve backward compatibility | PASS | Added legacy tick fallback when `deltaSeconds` is absent. |
+| Update backlog | PASS | `Delta - Runtime performance audit` marked complete. |
+| Update tool state if applicable | PASS | Not applicable; no tool tile/status changed. |
+| Produce governance reports | PASS | Summary, branch validation, checklist, validation lane, manual notes, Codex diff, changed-file list, and ZIP. |
+| Runtime validation | PASS | Targeted node checks and runtime tick test passed. |
+| No unrelated files | PASS | Changes are limited to runtime tick loop, its focused test, backlog, and reports. |
+| No branch deletion | PASS | Source branch retained. |
+
+## Compatibility Notes
+
+- `advanceRuntimeTick(...)` preserves the same public tick shape.
+- Callers with old tick objects still get a computed `deltaSeconds` value.
+- Invalid fixed-delta errors remain unchanged.

docs_build/dev/reports/PR_26175_DELTA_001_Runtime_Performance_Optimization-validation.md

@@ -0,0 +1,25 @@
+# PR_26175_DELTA_001 Validation Lane
+
+## Commands
+
+```powershell
+node --check src/engine/runtime/runtimeTickLoop.js
+node --check tests/engine/RuntimeTickLoop.test.mjs
+node tests/engine/RuntimeTickLoop.test.mjs
+```
+
+## Results
+
+| Command | Status |
+| --- | --- |
+| `node --check src/engine/runtime/runtimeTickLoop.js` | PASS |
+| `node --check tests/engine/RuntimeTickLoop.test.mjs` | PASS |
+| `node tests/engine/RuntimeTickLoop.test.mjs` | PASS |
+
+## Browser Validation
+
+SKIP - No browser UI files changed.
+
+## Playwright Validation
+
+SKIP - Runtime tick-loop internals are covered by the focused Node runtime test.

docs_build/dev/reports/PR_26175_DELTA_001_Runtime_Performance_Optimization.md

@@ -0,0 +1,42 @@
+# PR_26175_DELTA_001_Runtime_Performance_Optimization
+
+## Summary
+
+Team Delta completed a focused runtime performance optimization for the fixed-step runtime tick loop.
+
+The runtime now reuses the precomputed `deltaSeconds` value already stored on a tick when advancing frames. This avoids recalculating the fixed delta seconds on every frame while preserving compatibility for legacy tick objects that do not yet carry `deltaSeconds`.
+
+## Scope
+
+- Team: Delta
+- Backlog item: `Delta - Runtime performance audit`
+- Runtime file changed: `src/engine/runtime/runtimeTickLoop.js`
+- Test file changed: `tests/engine/RuntimeTickLoop.test.mjs`
+- Backlog updated: `docs_build/dev/ProjectInstructions/backlog/BACKLOG_MASTER.md`
+
+## Runtime Impact
+
+PASS - Fixed-step runtime advancement behavior remains backward compatible.
+
+- Existing tick objects from `createRuntimeTickLoop(...)` retain `deltaSeconds`.
+- `advanceRuntimeTick(...)` reuses that value.
+- Legacy tick objects without `deltaSeconds` still compute a valid fallback.
+- Invalid fixed-delta handling is unchanged.
+
+## Backlog Update
+
+PASS - `Delta - Runtime performance audit` is marked complete with this PR as the completion reference.
+
+## Tool State Update
+
+SKIP - No Build Path tool status or tool tile state changed. This PR affects runtime internals only.
+
+## Validation Summary
+
+PASS - Targeted runtime validation completed.
+
+See `PR_26175_DELTA_001_Runtime_Performance_Optimization-validation.md` for command details.
+
+## Branch Disposition
+
+Source branch should be retained after merge unless OWNER later approves branch deletion.

docs_build/dev/reports/PR_26175_DELTA_002_Shared_Runtime_Consolidation-branch-validation.md

@@ -0,0 +1,15 @@
+# PR_26175_DELTA_002 Branch Validation
+
+| Gate | Status | Evidence |
+| --- | --- | --- |
+| Current branch before work | PASS | `main` after PR_001 merge |
+| Worktree before work | PASS | Clean |
+| Local/origin sync before work | PASS | `0 0` |
+| Team ownership | PASS | Team Delta owns Runtime, Shared JS, and technical consolidation. |
+| Work branch | PASS | `PR_26175_DELTA_002_Shared_Runtime_Consolidation` |
+| Previous Delta PR closed | PASS | PR_001 was merged and `main` was verified before PR_002 started. |
+| Scope boundary | PASS | Shared runtime clone helper plus replay runtime adopters and focused test only. |
+
+## Instruction Reads
+
+PASS - All files under `docs_build/dev/ProjectInstructions/` were read before the Delta sequence, and updated instructions were reread after pulling latest `main`.

docs_build/dev/reports/PR_26175_DELTA_002_Shared_Runtime_Consolidation-manual-validation-notes.md

@@ -0,0 +1,9 @@
+# PR_26175_DELTA_002 Manual Validation Notes
+
+- Confirmed Team Delta ownership covers Shared JS and Runtime.
+- Confirmed replay runtime cloning duplicated local `structuredClone` calls before this PR.
+- Confirmed replay model and replay system now use the shared runtime clone helper.
+- Confirmed fallback behavior by temporarily disabling `globalThis.structuredClone` in the focused replay test.
+- Confirmed no browser-owned data, API contract, UI, or tool state changes were introduced.
+- Confirmed backlog completion reference was added for `Delta - Shared JS consolidation`.
+- Confirmed source branch disposition should remain `retained`.

docs_build/dev/reports/PR_26175_DELTA_002_Shared_Runtime_Consolidation-requirement-checklist.md

@@ -0,0 +1,19 @@
+# PR_26175_DELTA_002 Requirement Checklist
+
+| Requirement | Status | Notes |
+| --- | --- | --- |
+| Team Delta ownership only | PASS | Shared JS and runtime replay consolidation are Delta-owned. |
+| One PR purpose | PASS | Shared runtime clone consolidation only. |
+| Preserve backward compatibility | PASS | Added JSON fallback when `structuredClone` is unavailable. |
+| Update backlog | PASS | `Delta - Shared JS consolidation` marked complete. |
+| Update tool state if applicable | PASS | Not applicable; no tool tile/status changed. |
+| Produce governance reports | PASS | Summary, branch validation, checklist, validation lane, manual notes, Codex diff, changed-file list, and ZIP. |
+| Runtime validation | PASS | Focused node checks, replay system test, and final systems test passed. |
+| No unrelated files | PASS | Changes are limited to shared runtime clone, replay runtime adopters, focused test, backlog, and reports. |
+| No branch deletion | PASS | Source branch retained. |
+
+## Compatibility Notes
+
+- Public replay model shape is unchanged.
+- Replay frames remain deep-cloned before storage and output.
+- Fallback cloning supports runtime environments without native `structuredClone`.

docs_build/dev/reports/PR_26175_DELTA_002_Shared_Runtime_Consolidation-validation.md

@@ -0,0 +1,31 @@
+# PR_26175_DELTA_002 Validation Lane
+
+## Commands
+
+```powershell
+node --check src/shared/runtime/snapshotClone.js
+node --check src/engine/replay/ReplayModel.js
+node --check src/engine/replay/ReplaySystem.js
+node --check tests/replay/ReplaySystem.test.mjs
+node tests/replay/ReplaySystem.test.mjs
+node tests/final/FinalSystems.test.mjs
+```
+
+## Results
+
+| Command | Status |
+| --- | --- |
+| `node --check src/shared/runtime/snapshotClone.js` | PASS |
+| `node --check src/engine/replay/ReplayModel.js` | PASS |
+| `node --check src/engine/replay/ReplaySystem.js` | PASS |
+| `node --check tests/replay/ReplaySystem.test.mjs` | PASS |
+| `node tests/replay/ReplaySystem.test.mjs` | PASS |
+| `node tests/final/FinalSystems.test.mjs` | PASS |
+
+## Browser Validation
+
+SKIP - No browser UI files changed.
+
+## Playwright Validation
+
+SKIP - Runtime replay/shared helper behavior is covered by focused Node tests.