feat(block1): inventory walking skeleton + first quick-add slice

Stand up the Tanemaki monorepo and the first end-to-end vertical slice of
Block 1 (offline, encrypted inventory): add a seed → see it in a categorized,
searchable list → it persists → reopen and it's still there.

Architecture (state management like G1nkgo, adapted to Tane's reality):
- flutter_bloc (Cubit-first), but the encrypted Drift DB is the single source
  of truth; cubits stream from repositories (no hydrated_bloc/Hive, which would
  write plaintext at rest).
- get_it composition root; go_router; slang i18n (ES/EN, Weblate-friendly JSON).

Workspace & core:
- pub workspace: packages/commons_core (pure Dart) + apps/app_seeds (Flutter).
- commons_core primitives: UUIDv7 IdGen, Hybrid Logical Clock, Quantity value
  type (+ plant-aware QuantityKind), IdentityService root-seed stub.

Data & security:
- Drift schemaVersion=1 with all 10 Block-1 tables + common CRDT columns
  (HLC updated_at, last_author, tombstones); Movement append-only.
- SQLCipher via an injectable executor that refuses to open a plaintext DB;
  DB key + root seed in the OS keystore (separate secrets).
- Exported drift_schema_v1.json + migration scaffold.

Tests (near-TDD; nothing merges without tests):
- commons_core units (24), Drift migration test, "no plaintext at rest"
  security guard (runs where SQLCipher is present, skips otherwise),
  repository, widget, full quick-add flow, file-reopen persistence, and a
  no-hardcoded-strings i18n guard. GitLab CI: format + analyze + test + coverage.

Follow-on Block-1 stories (item detail/edit, species catalog, germination UI)
and all of Block 2 remain out of scope.

packages/commons_core/lib/src/ids/id_gen.dart

@@ -0,0 +1,16 @@
+import 'package:uuid/uuid.dart';
+
+/// Generates client-side, time-sortable row identifiers (UUIDv7).
+///
+/// Every mutable row in the model is keyed by a client-generated UUIDv7 —
+/// never an auto-increment (which would collide across peers). UUIDv7 embeds a
+/// millisecond timestamp in its most-significant bits, so lexical order
+/// approximates creation order, which suits CRDT sync and time-ordered queries.
+class IdGen {
+  IdGen({Uuid? uuid}) : _uuid = uuid ?? const Uuid();
+
+  final Uuid _uuid;
+
+  /// A fresh UUIDv7 string, e.g. `018f1a2b-...-7...-...`.
+  String newId() => _uuid.v7();
+}