[AZ-447] autodev Steps 1-4 baseline: docs, tests, refactor specs

Captures the full output of autodev existing-code Phase A through
Step 4 (Code Testability Revision) for the Azaion UI workspace:

- Step 1 Document: _docs/02_document/ (FINAL_report, architecture,
  glossary, components/, modules/, diagrams/, system-flows,
  module-layout) plus _docs/00_problem/ + _docs/01_solution/ +
  _docs/legacy/ + _docs/how_to_test + README.
- Step 2 Architecture Baseline: architecture_compliance_baseline.md.
- Step 3 Test Spec: _docs/02_document/tests/ (environment,
  test-data, blackbox/performance/resilience/security/
  resource-limit tests, traceability-matrix), enum_spec_snapshot,
  expected_results/results_report.md (98 rows), plus the
  run-tests.sh + run-performance-tests.sh runners.
- Step 4 Code Testability Revision: 01-testability-refactoring/
  run dir (list-of-changes C01-C07, deferred_to_refactor,
  analysis/research_findings + refactoring_roadmap) and the 7
  child task specs AZ-448..AZ-454 under _docs/02_tasks/todo/
  plus _dependencies_table.md.
- _docs/_autodev_state.md pins the cursor at Step 4 / refactor
  Phase 4 entry so /autodev resumes cleanly.

Epic AZ-447 (UI testability gates) tracks the 7 child tasks that
will land in subsequent commits.

Co-authored-by: Cursor <cursoragent@cursor.com>

_docs/02_document/components/00_foundation/description.md

@@ -0,0 +1,87 @@
+# 00 — Foundation
+
+## 1. High-Level Overview
+
+**Purpose**: Pure leaf modules every other component depends on — TypeScript domain types, framework-agnostic React hooks, and i18next setup. No HTTP, no React tree, no business logic.
+
+**Architectural Pattern**: Foundation / shared kernel.
+
+**Upstream dependencies**: none (intra-repo). External: `i18next`, `react-i18next`, `react`.
+
+**Downstream consumers**: every other `src/` component.
+
+## 2. Internal Interfaces
+
+### `src/types/index.ts`
+
+| Export | Kind | Purpose |
+|--------|------|---------|
+| `DetectionClass`, `Annotation`, `Affiliation`, `CombatReadiness`, `AnnotationStatus`, `AnnotationSource`, `MediaStatus`, `Flight`, `Waypoint`, `DatasetItem`, `User`, `Permission`, etc. | type / enum | Shared domain shape used by `api/`, providers, and every feature page. |
+
+> **CAVEAT — cross-cutting Step 4 work**. State.json records 4 enum-drift findings against the parent suite spec (`AnnotationStatus`, `Affiliation`, `CombatReadiness`, `MediaStatus`) plus a `Waypoint` shape mismatch. Owner of fix: this single file. The full target shapes live in `_docs/02_document/modules/src__features__annotations.md` findings #27–34 and `src__features__flights.md` finding #20.
+
+### `src/hooks/useDebounce.ts`
+
+| Export | Signature | Purpose |
+|--------|-----------|---------|
+| `useDebounce<T>(value: T, delay: number): T` | hook | Debounced value mirror. Used by Annotations search and Dataset filters. |
+
+### `src/hooks/useResizablePanel.ts`
+
+| Export | Signature | Purpose |
+|--------|-----------|---------|
+| `useResizablePanel(initialWidth: number, opts): { width, dragHandleProps }` | hook | Mouse-drag-resizable side panel. Used by Annotations and Dataset pages. Width is **not** persisted (finding #11 in `src__features__annotations.md`). |
+
+### `src/i18n/i18n.ts`
+
+| Export | Kind | Purpose |
+|--------|------|---------|
+| (default side-effect) | i18next init | Loads `en.json` + `ua.json`, wires `react-i18next`. Imported once by `main.tsx` for its side effect. |
+
+> **CAVEAT**. `lng: 'en'` is hardcoded; no language detector or persistence. `ua.json` exists as a translation target but is not selectable at runtime (finding #1 in `src__i18n__i18n.md`). This is a Step 4 testability/configurability fix.
+
+## 5. Implementation Details
+
+| Module | Notes |
+|--------|-------|
+| `types/index.ts` | Plain TypeScript. No runtime code. |
+| `useDebounce` | `setTimeout` + `clearTimeout` in `useEffect`. |
+| `useResizablePanel` | `mousemove` listener attached to `window` while dragging; min/max width clamped. |
+| `i18n/i18n.ts` | i18next + ICU plurals. Bundles loaded synchronously (small JSONs, ~100 keys each). |
+
+**State Management**: Stateless apart from the local hook state inside `useDebounce` / `useResizablePanel`. i18next's instance is module-level.
+
+**Key Dependencies**:
+
+| Library | Version | Purpose |
+|---------|---------|---------|
+| `i18next` | (per `package.json`) | Translation engine |
+| `react-i18next` | (per `package.json`) | React bindings; consumed via `useTranslation` in features |
+| `react` | 19 | Hooks runtime |
+
+## 7. Caveats & Edge Cases
+
+- Enum drift findings (cross-cutting). See state.json notes 2026-05-10 02:01Z and 02:13Z. Step 4 must reconcile against .NET service before patching `types/index.ts`.
+- `i18n` init is synchronous; if either bundle fails to load the app crashes at startup. No fallback.
+- `useResizablePanel` does not persist user-chosen width; resets every page nav.
+
+## 8. Dependency Graph
+
+**Must be implemented after**: nothing (Layer 0).
+
+**Can be implemented in parallel with**: itself (the 4 modules are independent).
+
+**Blocks**: every other component in this workspace.
+
+## 6. Extensions and Helpers
+
+`features/annotations/classColors.ts` was originally drafted as part of `06_annotations`, but per the Step 2 BLOCKING gate it has been lifted into its own component, **`11_class-colors`** (sibling shared kernel — see `components/11_class-colors/description.md`). The physical file location is unchanged — only the conceptual ownership moved. The proper physical home (a `src/shared/` or `src/components/detection/` directory) is deferred to Step 2.5 / Step 4 / Step 8.
+
+## Module Inventory
+
+| Path | Module Doc |
+|------|------------|
+| `src/types/index.ts` | `_docs/02_document/modules/src__types__index.md` |
+| `src/hooks/useDebounce.ts` | `_docs/02_document/modules/src__hooks__useDebounce.md` |
+| `src/hooks/useResizablePanel.ts` | `_docs/02_document/modules/src__hooks__useResizablePanel.md` |
+| `src/i18n/i18n.ts` | `_docs/02_document/modules/src__i18n__i18n.md` |