[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/modules/src__components__HelpModal.md

@@ -0,0 +1,64 @@
+# Module: `src/components/HelpModal.tsx`
+
+> **Source**: `src/components/HelpModal.tsx` (62 lines)
+> **Topo batch**: B2 (uses `react-i18next` for the language flag only; no intra-repo deps)
+
+## Purpose
+
+A modal dialog that surfaces annotation guidelines and the keyboard-shortcut cheat-sheet. Triggered from `Header.tsx` → "Help" entry. Replaces the legacy WPF `HelpWindow.xaml` (`_docs/legacy/wpf-era.md` §4).
+
+## Public interface
+
+```ts
+interface Props {
+  open: boolean
+  onClose: () => void
+}
+export default function HelpModal(props: Props): JSX.Element | null
+```
+
+When `open === false`, returns `null`. Otherwise renders a centered `<div>` overlay.
+
+## Internal logic
+
+- Reads `i18n.language` from `useTranslation()`; treats anything other than `'ua'` as English (`lang = i18n.language === 'ua' ? 'ua' : 'en'`).
+- `GUIDELINES`: a hardcoded array of 6 `{ en, ua }` rules covering annotation quality. **Hardcoded — not loaded via the `i18n` resource bundle**, despite the module already importing `useTranslation`. (Inconsistency vs. the rest of the SPA — flag for Step 4.)
+- Renders the guidelines as a numbered list and a 12-row keyboard-shortcut grid (`Space`, `← →`, `Ctrl + ← →`, `Enter`, …).
+- Click on the dim backdrop closes the modal; click inside is `stopPropagation`'d.
+- `Close` button is a styled `<button>` calling `onClose()`.
+
+## Dependencies
+
+- **Internal**: none.
+- **External**: `react-i18next` (for `useTranslation()` only — to detect the language; *not* for content lookup).
+
+## Consumers (intra-repo)
+
+- `src/components/Header.tsx` — owns `open` state and the trigger button.
+
+## Data models
+
+The `GUIDELINES` array — module-private. Each entry: `{ en: string, ua: string }`.
+
+## Configuration
+
+The keyboard-shortcut grid hardcodes the same shortcut taxonomy that `_docs/ui_design/README.md` §"Keyboard Shortcuts" enumerates. Verify parity during Step 4.
+
+## External integrations
+
+None.
+
+## Security
+
+None directly. Note that ESCAPE-key handling appears in the *sibling* `ConfirmDialog` but **not** here — Esc currently does NOT close `HelpModal`. Backdrop click is the only dismiss path beyond the Close button. Inconsistent UX; flag for Step 4 verification against the UI spec.
+
+## Tests
+
+None.
+
+## Notes / open questions
+
+- The 6 guidelines stored as `{ en, ua }` literals duplicate the Annotation Quality Guidelines documented in `_docs/ui_design/README.md` §"Annotation Quality Guidelines" (which lists six rules with subtly different wording). Choose one source of truth in Step 5; preferred is to lift the strings into `en.json` / `ua.json` like the rest of the SPA.
+- The `<h2>` "How to Annotate" heading is hardcoded English; should also be translated.
+- The `lang === 'ua' ? 'ua' : 'en'` branch silently treats every non-Ukrainian language as English — only correct as long as exactly two locales exist. If a third locale is added, this needs to use the `i18n` lookup table.
+- Width is hardcoded `w-[500px]` and `max-h-[80vh]`. Does not adapt to mobile breakpoints documented in `_docs/ui_design/README.md` §"Responsive Breakpoints" (640px). Flag.