adapter-sqlite: all repo implementations + wire fn + migrations copy

migrations_sqlite/20260319000001_multi_provider_instances.sql

@@ -0,0 +1,17 @@
+-- Recreate provider_configs with per-instance id as PK
+CREATE TABLE provider_configs_new (
+  id            TEXT PRIMARY KEY,
+  provider_type TEXT NOT NULL,
+  config_json   TEXT NOT NULL,
+  enabled       INTEGER NOT NULL DEFAULT 1,
+  updated_at    TEXT NOT NULL
+);
+INSERT INTO provider_configs_new (id, provider_type, config_json, enabled, updated_at)
+  SELECT provider_type, provider_type, config_json, enabled, updated_at
+  FROM provider_configs;
+DROP TABLE provider_configs;
+ALTER TABLE provider_configs_new RENAME TO provider_configs;
+
+-- Scope local_files_index entries by provider instance
+ALTER TABLE local_files_index ADD COLUMN provider_id TEXT NOT NULL DEFAULT 'local';
+CREATE INDEX IF NOT EXISTS idx_local_files_provider ON local_files_index(provider_id);