feat(db): schema user_weight_profiles (#114 sub-PR 1/4 — foundation) (#136)

Per #114 Custom POI weights — Макс feedback "садики и Мегамарт должны
иметь разные веса". Sub-PR 1/4 per feedback_split_big_issues:

1. **#114 sub-PR 1 (this)**: schema migration
2. #114 sub-PR 2: backend Pydantic models + CRUD service
3. #114 sub-PR 3: POST /parcels/{cad}/analyze?profile= override + admin endpoint
4. #114 sub-PR 4: frontend 25 sliders UI + live preview

## Schema

`data/sql/90_user_weight_profiles.sql`:

- Table `user_weight_profiles` — SERIAL PK + user_id + profile_name +
  weights JSONB + is_default + timestamps
- Unique constraint (user_id, profile_name)
- B-tree index user_idx
- Partial index `WHERE is_default = TRUE` (fast default lookup)
- Trigger auto-updated_at via `set_updated_at()` function

## Compat with existing POI categories

`weights` JSONB compatible с current `_POI_WEIGHTS` const в
`backend/app/api/v1/parcels.py`:
- school 1.5, kindergarten 1.5, pharmacy 0.8, hospital 0.6
- shop_mall 1.2, shop_supermarket 1.0, shop_small 0.5
- park 1.8, bus_stop 0.3, metro_stop 1.5, tram_stop -0.5

## Idempotency

- BEGIN/COMMIT обёртка
- IF NOT EXISTS на CREATE TABLE/INDEX
- DROP TRIGGER IF EXISTS → CREATE TRIGGER (safe re-run)
- CREATE OR REPLACE FUNCTION (idempotent)

## Apply

```bash
psql postgresql://gendesign:...@localhost:15432/gendesign \
  -f data/sql/90_user_weight_profiles.sql
```

После apply таблица inert (нет backend code yet). Sub-PR 2 добавит CRUD.

## Vault

`code/schemas/Schema_User_Weight_Profiles.md` — created (status:
ready_to_apply, full sub-PR plan).

Refs: #114

Co-authored-by: lekss361 <claudestars@proton.me>

data/sql/90_user_weight_profiles.sql

@@ -0,0 +1,66 @@
+-- 90_user_weight_profiles.sql
+-- User-defined POI weight profiles для site_finder/analyze_parcel.
+-- Per #114 (Макс feedback): разные веса для разных категорий (садики ≠ Мегамарт).
+--
+-- Apply order: после 89_drop_dead_brin_rosreestr_deals.sql
+-- Dependencies: нет (standalone table, no FK to other tables)
+--
+-- POI categories compatible with _POI_WEIGHTS in backend/app/api/v1/parcels.py:
+--   school, kindergarten, pharmacy, hospital, shop_mall, shop_supermarket,
+--   shop_small, park, bus_stop, metro_stop, tram_stop
+--
+-- Idempotent: safe to run multiple times.
+
+BEGIN;
+
+CREATE TABLE IF NOT EXISTS user_weight_profiles (
+    id           SERIAL PRIMARY KEY,
+    user_id      TEXT NOT NULL,  -- пока admin token / простой ID; auth в Sprint 5
+    profile_name TEXT NOT NULL,
+    weights      JSONB NOT NULL DEFAULT '{}'::jsonb,
+    is_default   BOOLEAN NOT NULL DEFAULT FALSE,
+    description  TEXT,
+    created_at   TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at   TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (user_id, profile_name)
+);
+
+CREATE INDEX IF NOT EXISTS user_weight_profiles_user_idx
+    ON user_weight_profiles (user_id);
+
+-- Partial index для быстрого fetch default profile per user
+CREATE INDEX IF NOT EXISTS user_weight_profiles_default_idx
+    ON user_weight_profiles (user_id) WHERE is_default = TRUE;
+
+-- Trigger function для auto-update updated_at (shared, reusable across tables)
+CREATE OR REPLACE FUNCTION set_updated_at() RETURNS TRIGGER AS $$
+BEGIN
+    NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+-- Drop trigger если ранее существовал (idempotent)
+DROP TRIGGER IF EXISTS user_weight_profiles_updated_at ON user_weight_profiles;
+CREATE TRIGGER user_weight_profiles_updated_at
+    BEFORE UPDATE ON user_weight_profiles
+    FOR EACH ROW EXECUTE FUNCTION set_updated_at();
+
+COMMENT ON TABLE user_weight_profiles IS
+    'POI weight profiles для site_finder. Per #114 (Макс feedback). '
+    'weights = {"school": 1.5, "kindergarten": 1.5, "shop_mall": 1.2, ...}';
+
+COMMENT ON COLUMN user_weight_profiles.weights IS
+    'JSONB map: poi_category → weight (float, typically -1.5..2.5). '
+    'Совместимо с _POI_WEIGHTS default в backend/app/api/v1/parcels.py. '
+    'Категории: school, kindergarten, pharmacy, hospital, shop_mall, '
+    'shop_supermarket, shop_small, park, bus_stop, metro_stop, tram_stop.';
+
+COMMENT ON COLUMN user_weight_profiles.user_id IS
+    'Простой строковый ID пользователя. Full auth integration — Sprint 5.';
+
+COMMENT ON COLUMN user_weight_profiles.is_default IS
+    'TRUE = профиль используется по умолчанию для этого user_id. '
+    'Partial index user_weight_profiles_default_idx ускоряет lookup.';
+
+COMMIT;