Add unified Stella Assistant: mascot + search + AI chat as one

Merge three disconnected help surfaces (Stella mascot, Ctrl+K search,
Advisory AI chat) into one unified assistant. Mascot is the face,
search is its memory, AI chat is its voice.

Backend:
- DB schema (060/061): tips, greetings, glossary, tours, user_state
  tables with 189 tips + 101 greetings seed data
- REST API: GET tips/glossary/tours, GET/PUT user-state with
  longest-prefix route matching and locale fallback
- Admin endpoints: CRUD for tips, glossary, tours (SetupAdmin policy)

Frontend:
- StellaAssistantService: unified mode management (tips/search/chat),
  API-backed tips with static fallback, i18n integration
- Three-mode mascot component: tips, inline search, embedded chat
- StellaGlossaryDirective: DB-backed tooltip annotations for domain terms
- Admin tip editor: CRUD for tips/glossary/tours in Console Admin
- Tour player: step-through guided tours with element highlighting

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/Platform/__Libraries/StellaOps.Platform.Database/Migrations/Release/060_StellaAssistant.sql

@@ -0,0 +1,105 @@
+-- SPRINT_20260329_007 / Unified Stella Assistant
+-- DB-backed contextual tips, glossary, tours, and user state for the Stella mascot.
+-- Replaces hardcoded English-only tips with locale-aware, admin-editable content.
+
+CREATE SCHEMA IF NOT EXISTS platform;
+
+-- ─── Tips: page/tab-level contextual help ───────────────────────────────────
+
+CREATE TABLE IF NOT EXISTS platform.assistant_tips (
+    tip_id          UUID         PRIMARY KEY DEFAULT gen_random_uuid(),
+    route_pattern   TEXT         NOT NULL,
+    context_trigger TEXT,
+    locale          VARCHAR(10)  NOT NULL DEFAULT 'en-US',
+    sort_order      INT          NOT NULL DEFAULT 0,
+    title           TEXT         NOT NULL,
+    body            TEXT         NOT NULL,
+    action_label    TEXT,
+    action_route    TEXT,
+    learn_more_url  TEXT,
+    is_active       BOOLEAN      NOT NULL DEFAULT TRUE,
+    product_version VARCHAR(32),
+    tenant_id       VARCHAR(128) NOT NULL DEFAULT '_system',
+    created_at      TIMESTAMPTZ  NOT NULL DEFAULT now(),
+    updated_at      TIMESTAMPTZ  NOT NULL DEFAULT now(),
+    created_by      VARCHAR(256) NOT NULL DEFAULT 'system',
+
+    CONSTRAINT ux_assistant_tips_route_ctx_locale_order
+        UNIQUE (tenant_id, route_pattern, context_trigger, locale, sort_order)
+);
+
+CREATE INDEX IF NOT EXISTS ix_assistant_tips_route_locale
+    ON platform.assistant_tips (route_pattern, locale)
+    WHERE is_active;
+
+CREATE INDEX IF NOT EXISTS ix_assistant_tips_context
+    ON platform.assistant_tips (context_trigger)
+    WHERE context_trigger IS NOT NULL AND is_active;
+
+-- ─── Greetings: per-page greeting text ──────────────────────────────────────
+
+CREATE TABLE IF NOT EXISTS platform.assistant_greetings (
+    greeting_id     UUID         PRIMARY KEY DEFAULT gen_random_uuid(),
+    route_pattern   TEXT         NOT NULL,
+    locale          VARCHAR(10)  NOT NULL DEFAULT 'en-US',
+    greeting_text   TEXT         NOT NULL,
+    is_active       BOOLEAN      NOT NULL DEFAULT TRUE,
+    tenant_id       VARCHAR(128) NOT NULL DEFAULT '_system',
+    created_at      TIMESTAMPTZ  NOT NULL DEFAULT now(),
+
+    CONSTRAINT ux_assistant_greetings_route_locale
+        UNIQUE (tenant_id, route_pattern, locale)
+);
+
+-- ─── Glossary: domain term definitions ──────────────────────────────────────
+
+CREATE TABLE IF NOT EXISTS platform.assistant_glossary (
+    term_id         UUID         PRIMARY KEY DEFAULT gen_random_uuid(),
+    term            VARCHAR(128) NOT NULL,
+    locale          VARCHAR(10)  NOT NULL DEFAULT 'en-US',
+    definition      TEXT         NOT NULL,
+    extended_help   TEXT,
+    related_terms   TEXT[]       NOT NULL DEFAULT '{}',
+    related_routes  TEXT[]       NOT NULL DEFAULT '{}',
+    is_active       BOOLEAN      NOT NULL DEFAULT TRUE,
+    tenant_id       VARCHAR(128) NOT NULL DEFAULT '_system',
+    created_at      TIMESTAMPTZ  NOT NULL DEFAULT now(),
+
+    CONSTRAINT ux_assistant_glossary_term_locale
+        UNIQUE (tenant_id, term, locale)
+);
+
+CREATE INDEX IF NOT EXISTS ix_assistant_glossary_locale
+    ON platform.assistant_glossary (locale)
+    WHERE is_active;
+
+-- ─── Tours: guided walkthroughs ─────────────────────────────────────────────
+
+CREATE TABLE IF NOT EXISTS platform.assistant_tours (
+    tour_id         UUID         PRIMARY KEY DEFAULT gen_random_uuid(),
+    tour_key        VARCHAR(128) NOT NULL,
+    locale          VARCHAR(10)  NOT NULL DEFAULT 'en-US',
+    title           TEXT         NOT NULL,
+    description     TEXT         NOT NULL,
+    steps           JSONB        NOT NULL DEFAULT '[]',
+    is_active       BOOLEAN      NOT NULL DEFAULT TRUE,
+    tenant_id       VARCHAR(128) NOT NULL DEFAULT '_system',
+    created_at      TIMESTAMPTZ  NOT NULL DEFAULT now(),
+
+    CONSTRAINT ux_assistant_tours_key_locale
+        UNIQUE (tenant_id, tour_key, locale)
+);
+
+-- ─── User state: per-user mascot preferences ───────────────────────────────
+
+CREATE TABLE IF NOT EXISTS platform.assistant_user_state (
+    user_id         VARCHAR(256) NOT NULL,
+    tenant_id       VARCHAR(128) NOT NULL,
+    seen_routes     TEXT[]       NOT NULL DEFAULT '{}',
+    completed_tours TEXT[]       NOT NULL DEFAULT '{}',
+    tip_positions   JSONB        NOT NULL DEFAULT '{}',
+    dismissed       BOOLEAN      NOT NULL DEFAULT FALSE,
+    last_seen_at    TIMESTAMPTZ  NOT NULL DEFAULT now(),
+
+    PRIMARY KEY (user_id, tenant_id)
+);