feat: 5-day theme-level onboarding track from the "New here?" card (#30)

A self-paced onboarding track that introduces a new employee to every KB
theme in breadth (not depth), so they grasp how Respellion works day to
day and week to week. Offered as a CTA inside the Dashboard "New here?"
explainer card; always available regardless of enrollment.

Design:
- Theme is the trackable unit; the 5 "days" are a read-time presentation
  grouping, so re-chunking never loses progress. Completion is stored per
  theme in onboarding_completions.
- Per-theme overview generated lazily on first open (fast-tier
  emit_onboarding_overview tool), cached in onboarding_overviews keyed by
  theme + a topics_fingerprint that triggers regeneration when the theme's
  topic set changes.
- Reachable via /onboarding-track using the existing skipEnrollmentGate
  prop, decoupled from the 26-week curriculum (distinct from /onboarding,
  the enrollment page).

Backend:
- pb_migrations/1781200000_created_onboarding.js: two collections with
  authenticated-only rules and unique indexes; TEXT team_member_id (no
  relation) per the post-#18/#27 convention. Mirrored in
  scripts/setup-pb-collections.mjs.
- src/lib/onboardingService.js: pure helpers (orderThemes,
  distributeThemesIntoDays, computeTopicsFingerprint,
  computeOnboardingProgress, buildOnboardingPlan) + generation + I/O.
- db.js onboarding helpers use pb.filter() bindings (theme is free text).
- LLM tool + Zod schema + registry + simulation stub.

Frontend:
- src/pages/OnboardingTrack.jsx (day list, per-theme overview, completion
  banner, progress ring/day bar).
- Dashboard "New here?" card CTA + X/5-days progress chip (hidden when the
  KB has no themes).

Docs: data-model, generation-spec (§D), frontend-spec updated.

Verified: 22 new unit tests (npm test 134/134), eslint clean on changed
files, npm run build OK, PocketBase v0.30.4 boot applies the migration
(collections + unique indexes + authed rules confirmed), and a backend
contract check (upsert idempotency, unique-index guard, special-char
theme filtering).

Closes #30

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/data-model.md

@@ -212,6 +212,34 @@ Best-effort telemetry for every Anthropic call (written by `callLLM`).
 
 ---
 
+### `onboarding_overviews`
+Cached, breadth-first per-theme overview for the onboarding track (issue #30).
+One row per theme, shared across all users. Generated lazily on first open.
+
+| Field | Type | Notes |
+|---|---|---|
+| theme | text | canonical theme name (from `topics.theme`); **unique** |
+| content | json | validated `onboardingOverviewSchema` payload (title, what_it_is, why_it_matters, key_points, topics_covered) |
+| topics_fingerprint | text | stable hash of the theme's sorted topic ids; a mismatch triggers regeneration |
+
+Unique index on `(theme)`. Rules: authenticated-only (`@request.auth.id != ""`).
+
+---
+
+### `onboarding_completions`
+Per-user, per-theme completion marker for the onboarding track (issue #30).
+
+| Field | Type | Notes |
+|---|---|---|
+| team_member_id | text | the employee — **plain text**, not a relation (admins can delete members; orphan rows are harmless) |
+| theme | text | the theme marked complete |
+
+Unique index on `(team_member_id, theme)` → idempotent. Rules: authenticated-only.
+Completion is tracked per **theme**, not per day; the 5 "days" are a read-time
+presentation grouping, so re-chunking never loses progress.
+
+---
+
 ## Dropped / legacy collections
 
 These existed in earlier iterations and have been removed. Their `db.js` helpers

docs/frontend-spec.md

@@ -10,8 +10,9 @@ A React 19 SPA built with Vite, routed by React Router 7. Entry: `src/main.jsx`
 | Route | Screen | Access |
 |---|---|---|
 | `/login` | `Login.jsx` | public |
-| `/onboarding` | `Onboarding.jsx` | logged-in, not yet enrolled |
+| `/onboarding` | `Onboarding.jsx` | logged-in, not yet enrolled (enrollment page) |
 | `/` | `Dashboard.jsx` | enrolled user |
+| `/onboarding-track` | `OnboardingTrack.jsx` | any logged-in user, **any enrollment** (`skipEnrollmentGate`) |
 | `/learn` | `Leren.jsx` | enrolled user |
 | `/test` | `Testen.jsx` | enrolled user |
 | `/leaderboard` | `Leaderboard.jsx` | enrolled user |
@@ -20,9 +21,14 @@ A React 19 SPA built with Vite, routed by React Router 7. Entry: `src/main.jsx`
 `ProtectedRoute`:
 - redirects to `/login` if not authenticated;
 - redirects to `/onboarding` if `enrollment_status !== 'active'` — **except** admins
-  heading to the admin panel, who are exempt;
+  heading to the admin panel, and routes passing `skipEnrollmentGate` (the onboarding
+  track), which are exempt;
 - enforces `requireAdmin` for `/admin`.
 
+> `/onboarding` (enrollment) and `/onboarding-track` (the 5-day theme intro) are
+> distinct. The track is decoupled from enrollment on purpose so it also works as a
+> refresher for existing staff.
+
 Navigation chrome (top bar + mobile bottom nav) is rendered by `ProtectedRoute`.
 `ChatLauncher` (R42) is mounted globally.
 
@@ -51,7 +57,17 @@ enrolled are redirected to `/`. See `docs/curriculum-spec.md`.
 ## Employee screens
 
 - **Dashboard** — current cycle/week, assigned topic, cycle progress ring, quick
-  links to Learn and Test, mini leaderboard, recent activity.
+  links to Learn and Test, mini leaderboard, recent activity. The dismissible
+  "New here?" explainer card also carries the **onboarding-track CTA** (a progress
+  chip `X/5 days` + a Start/Continue/Review button linking to `/onboarding-track`),
+  shown only when the KB has themes to introduce.
+- **Onboarding Track (`/onboarding-track`)** — a self-paced, breadth-first tour of
+  every theme, grouped into ≤5 day cards (`OnboardingTrack.jsx`). Opening a theme
+  lazily generates a short overview (what it is / why it matters for daily & weekly
+  work / key points / topics) and offers "Mark as done"; a progress ring + day bar
+  track completion, and a completion banner shows when every theme is done. Available
+  to any logged-in user regardless of enrollment; completion is stored per theme in
+  `onboarding_completions`. See `docs/generation-spec.md §D`.
 - **Learning Station (`/learn`)** — the week's required topic + the rest of the
   knowledge library; opening a topic shows the micro-learning selector
   (`src/components/micro_learning/`). Completing ≥1 micro-learning marks the week done.

docs/generation-spec.md

@@ -74,6 +74,29 @@ explanation, difficulty }`.
 
 ---
 
+## D. Onboarding overviews — `src/lib/onboardingService.js`
+
+Powers the 5-day onboarding track (issue #30): a short, breadth-first overview of
+**one theme** for a brand-new employee — deliberately light, not a deep lesson.
+
+- **Tool:** `emit_onboarding_overview` · **tier:** `fast` (Haiku) · `maxTokens: 1500`,
+  60s timeout · schema `onboardingOverviewSchema`.
+- **Shape:** `{ title, what_it_is, why_it_matters, key_points[3–5], topics_covered[{topic_id,label}] }`.
+  `why_it_matters` is framed around day-to-day / week-to-week work at Respellion.
+- **Cache:** `onboarding_overviews`, one row per theme, keyed by theme name plus a
+  `topics_fingerprint` (stable hash of the theme's sorted topic ids).
+  `getOrGenerateOnboardingOverview(theme, topics, {force})` returns the cached row when
+  the fingerprint matches; a mismatch (topic added/removed) or `force` regenerates.
+- **Simulation:** `emit_onboarding_overview` has a stub in `SIMULATION_TOOL_STUBS`.
+
+Theme ordering + day grouping are pure helpers in the same module
+(`orderThemes`, `distributeThemesIntoDays`, `computeTopicsFingerprint`,
+`computeOnboardingProgress`, `buildOnboardingPlan`), unit-tested in
+`src/lib/__tests__/onboardingService.test.js`. Completion is recorded per **theme**
+in `onboarding_completions` (`{ team_member_id, theme }`), not per day.
+
+---
+
 ## Shared infrastructure (`src/lib/llm.js`)
 
 - **Tiers:** `fast` (Haiku 4.5), `standard` (Sonnet 4.6), `reasoning` (Opus 4.7);