Phase 0: lock platform contract, naming convention, and style enforcement

Establishes the framework's foundation as a multi-site adoptable platform.

ADRs (migrations/adr/):
- ADR-001 (ACCEPTED): Asset is the platform contract; Machine retires.
  Three relationship types (partof, controls, connectedto) with free-text
  label, position-resolution chain (asset > related > location),
  hierarchical locations, sibling-bay propagation.
- ADR-002 (ACCEPTED): Plugin contract semver via __contract_version__.
- ADR-003 (ACCEPTED): Hybrid plugin distribution (in-tree bundled +
  filesystem-based external).
- ADR-004 (ACCEPTED): Per-site instances, not multi-tenant.
- ADR-005 (ACCEPTED): Equipment plugin (manufacturing) split from
  measuringtools plugin (metrology). Subtype-table pattern for protocol
  data (FOCAS, CLM, MTConnect).
- ADR-006 (ACCEPTED): Plugin collector contract via get_collector_schema
  hook with API-key auth and identity-based upsert.

Naming convention v1 (CONTRIBUTING.md):
- DB tables/columns: lowercase concatenated, no underscores or dashes
- DB-mirrored Python/JS variables match column names exactly; pure code
  follows host-language convention (PEP 8 / camelCase)
- Closed acronym allowlist (universal + shop-floor domain), banned
  shorthand list with suffix exception (printers_bp etc allowed)
- Plain ASCII everywhere: chat, docs, comments, string literals

Style enforcement (scripts/check-naming-and-style.sh):
- Pre-commit-runnable check script: non-ASCII, banned shorthand,
  snake_case DB names, snake_case API params in frontend
- Fixes 14 violations across 11 files (Unicode arrows, snake_case
  params, ctx -> canvasContext, res -> response, req -> request_obj)

Project state (CLAUDE.md, README.md, frontend/CLAUDE.md):
- De-staled CLAUDE.md to reflect actual current state
- README unifies DB story (MySQL canonical, SQLite test-only)
- frontend/CLAUDE.md points at root convention

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -131,13 +131,15 @@ npm run build
 
 ### Database
 
+ShopDB Flask uses MySQL 5.6+ as the canonical database. SQLite is used only for the test suite (`TestingConfig` in `shopdb/config.py` points at an in-memory SQLite). Do not run dev or production against SQLite.
+
 The database schema is exported in `database/schema.sql`. To initialize:
 
 ```bash
 mysql -u root -p shopdb_flask < database/schema.sql
 ```
 
-To import data from the legacy ShopDB MySQL database:
+To import data from the legacy ShopDB MySQL database (one-time, see `migrations/DATA_MIGRATION_GUIDE.md`):
 
 ```bash
 python scripts/import_from_mysql.py