Unified Quote Journal (parts_log) v3

- New unified append-only quote log table parts_log replaces three
  separate log tables (stock_log, partnumber_log_competitors, lot_log)
- Migrations 042-049: extend supplier, create parts_log/import_formats/
  ignore_rules, rework qt_lot_metadata composite PK, add lead_time_weeks
  to pricelist_items, backfill data, migrate ignore rules
- New services: PartsLogBackfillService, ImportFormatService,
  UnifiedImportService; new world pricelist type (all supplier types)
- qt_lot_metadata PK changed to (lot_name, pricelist_type); all queries
  now filter WHERE pricelist_type='estimate'
- Fix pre-existing bug: qt_component_usage_stats column names
  quotes_last30d/quotes_last7d (no underscore) — added explicit gorm tags
- Bible: full table inventory, baseline schema snapshot, updated pricelist/
  data-rules/api/history/architecture docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

migrations/042_extend_supplier.sql

@@ -0,0 +1,29 @@
+-- Extend supplier table for unified quote journal.
+-- Adds supplier_code (symbolic identifier), supplier_type, price_uplift,
+-- default_lead_time_weeks, default_import_format_code, and is_active.
+
+-- Step 1: add columns without unique constraint (IF NOT EXISTS for idempotency)
+ALTER TABLE supplier
+    ADD COLUMN IF NOT EXISTS supplier_code VARCHAR(100) NOT NULL DEFAULT ''
+        COMMENT 'Short symbolic code: treolan, haoqian-jevy, netwell',
+    ADD COLUMN IF NOT EXISTS supplier_type ENUM('trader','self','competitor') NOT NULL DEFAULT 'trader',
+    ADD COLUMN IF NOT EXISTS price_uplift DECIMAL(8,4) NOT NULL DEFAULT 1.0000
+        COMMENT 'Price divisor at import: raw_price / price_uplift = USD. trader=1, self=1, competitor=1.3',
+    ADD COLUMN IF NOT EXISTS default_lead_time_weeks INT NULL
+        COMMENT 'NULL means not set (not equal to 0). self=0, competitor=2, trader=NULL',
+    ADD COLUMN IF NOT EXISTS default_import_format_code VARCHAR(100) NULL
+        COMMENT 'FK to qt_import_formats.format_code',
+    ADD COLUMN IF NOT EXISTS is_active TINYINT(1) NOT NULL DEFAULT 1;
+
+-- Step 2: add non-unique index if missing
+ALTER TABLE supplier
+    ADD INDEX IF NOT EXISTS idx_supplier_type (supplier_type);
+
+-- Step 3: seed supplier_code from supplier_name for existing rows that still have empty code
+UPDATE supplier
+SET supplier_code = LOWER(REPLACE(REPLACE(TRIM(supplier_name), ' ', '-'), '_', '-'))
+WHERE supplier_code = '';
+
+-- Step 4: add unique index after codes are populated
+ALTER TABLE supplier
+    ADD UNIQUE INDEX IF NOT EXISTS uq_supplier_code (supplier_code);