refactor: extract DataIO IIFE module (Phase 1 PR5/7)

[cheerc]

Phase 1 PR5: DataIO IIFE Extraction

Issue: refs #129 (Phase 1, Wave B)
Plan: docs/plans/2026-06-24-phase1-iife-refactoring.md §PR5

Summary

Extract 5 data I/O methods from JavaScript.html into a new DataIO.js.html IIFE module:

Method	Type	Purpose
loadVersions	async	Load version history from server
handleLoadVersion	async	Restore a historical version
saveDataToLocal	sync	Persist working data to localStorage
loadDataFromServer	async	Fetch data from server via ServerApi
saveDataToServer	async	Save data to server with conflict detection

Pattern

Standard IIFE pattern established in PR1-PR3:

(function(App) {
  App.methodName = function() { ... };
})(App);

All this.xxx references → App.xxx (IIFE closure).

Changed Files

File	Change
DataIO.js.html	New — 5 methods as IIFE
JavaScript.html	Remove 5 methods, add movement comments
Index.html	Add DataIO.js include (after DataCollection.js, before App.init())
tests/unit/appWiringContracts.test.js	Move 5 methods to IIFE_EXTRACTED, update count 26→21
tests/unit/asyncMethodsWiring.test.js	Load DataIO source, split JS_HTML/DATA_IO method lists
tests/unit/lifecycleRegression.test.js	Load DataIO source, update Phase B/E/F to use App.xxx patterns
tests/helpers/sourceAnalysis.js	Add IIFE pattern support to extractMethodBody

Verification

• npm test — 1147 tests, all green ✅
• npx eslint --ext .html . — 0 errors ✅
• bash scripts/check-structure.sh — all files present ✅
• Scope gate: 7 files changed (expected), no build artifacts

Dependencies

• Circular dependency with ScheduleManager (PR6): resolved via App.xxx mutual references (both close over same App object)
• ⚠️ PR4 (FilterEngine) is parallel — modifies different regions of JavaScript.html. Whichever merges second needs rebase.

ESLint Baseline

0 errors, 8 warnings (all pre-existing: unused vars in Modals.js.html and UI.js.html).

follows spec

[cheerc]

✅ VERIFIED

Reviewed HEAD: 3a0478a04b6ebb5256a29d52c2d364e3c184c0b1
Reviewer: cb-team-reviewer
Audit mode: standard (D2)

Files Reviewed (7)

• DataIO.js.html (new, +216) — IIFE module with 5 extracted data I/O methods
• JavaScript.html (-185) — removed 5 methods, added movement comments
• Index.html (+1) — include line for DataIO.js
• tests/helpers/sourceAnalysis.js (+10/-1) — IIFE pattern support in extractMethodBody
• tests/unit/appWiringContracts.test.js (+6/-7) — IIFE_EXTRACTED set, counts 26→21
• tests/unit/asyncMethodsWiring.test.js (+63/-18) — split JS_HTML/DATA_IO method lists
• tests/unit/lifecycleRegression.test.js (+28/-27) — source + this→App patterns

Stage 1 — Correctness

• All 5 methods correctly extracted with this → App conversion (0 residual this.)
• IIFE pattern (function(App) { ... })(App) consistent with PR1-PR4
• Load order: DataCollection.js → DataIO.js → App.init() ✓
• Circular dependency with ScheduleManager correctly resolved via runtime App.xxx calls
• Callers in JavaScript.html (L61 loadDataFromServer, L141/641 saveDataToLocal) work via this === App
• Callers in Interaction.js.html use app.xxx (captured App ref) — works since methods attached before init
• Test count: 48 - 7(PR1) - 4(PR2) - 11(PR3) - 5(PR5) = 21 ✓
• saveDataToServer correctly reclassified from EXTRACTED_TO_LIB → IIFE_EXTRACTED
• sourceAnalysis.js extractMethodBody IIFE fallback pattern is correct and non-breaking
• asyncMethodsWiring: resolveSource helper correctly routes to dataIOSource
• lifecycleRegression: Phase B/E/F patterns updated this\\. → App\\. with correct source
• No conflict markers in any of 7 files

Stage 2 — Adversarial

• Circular dependency safe: DataIO↔ScheduleManager methods resolve at call time, not load time
• delete App.schedules[id].lastModified in loadDataFromServer — same pre-existing logic, only reference changed
• saveResult?.error optional chaining preserved from original
• Conflict handling showConfirm(saveResult.error, true) — XSS-safe comment preserved, not introduced by this PR
• extractMethodBody duplication (asyncMethodsWiring vs sourceAnalysis.js) is pre-existing; both correctly updated

Note

⚠️ PR4 (FilterEngine) and PR5 (DataIO) modify overlapping files (JavaScript.html, Index.html, appWiringContracts.test.js). Whichever merges second will need a rebase — as documented in PR description.

Evidence

• ran: gh pr checks 149 → validate: SUCCESS
• ran: grep this\\. DataIO.js.html → no matches (exit 1)
• ran: conflict marker scan (7 files) → all clean
• ran: grep callers in Interaction.js.html → 10 references via app.xxx (correct pattern)
• cited: DataIO.js.html:22 — (function(App) { (IIFE entry)
• cited: DataIO.js.html:216 — })(App); (IIFE closure)
• cited: Index.html:479 — DataIO.js after DataCollection.js
• cited: appWiringContracts.test.js:132 — expect(publicMethods.length).toBe(21) (count verification)
• cited: lifecycleRegression.test.js:95 — App\\.schedules (this→App pattern confirmed)