refactor(db): consolidate database migrations from 6 to 3

- Add missing migrations table creation to 001_initial migration
- Consolidate migrations 003-006 into single 003_active_did_separation migration
- Rename migration for better clarity and logical grouping
- Preserve all original SQL operations and data integrity constraints
- Reduce migration complexity while maintaining functionality

This consolidation improves maintainability by grouping related schema changes
into logical atomic operations, reducing the total migration count by 50%.

src/db-sql/migration.ts

@@ -117,6 +117,11 @@ const MIGRATIONS = [
         id TEXT PRIMARY KEY,
         blobB64 TEXT
       );
+      
+      CREATE TABLE IF NOT EXISTS migrations (
+        name TEXT PRIMARY KEY,
+        applied_at TEXT NOT NULL DEFAULT (datetime('now'))
+      );
       `,
   },
   {
@@ -126,8 +131,12 @@ const MIGRATIONS = [
     `,
   },
   {
-    name: "003_active_did_separate_table",
+    name: "003_active_did_separation",
     sql: `
+      -- CONSOLIDATED MIGRATION: Combines original migrations 003, 004, 005, and 006
+      -- This migration handles the complete separation of activeDid from settings
+      -- and establishes proper data integrity constraints
+      
       -- Create new active_identity table with proper constraints
       CREATE TABLE IF NOT EXISTS active_identity (
         id INTEGER PRIMARY KEY CHECK (id = 1),
@@ -150,40 +159,22 @@ const MIGRATIONS = [
           lastUpdated = datetime('now')
       WHERE id = 1 
       AND EXISTS (SELECT 1 FROM settings WHERE id = 1 AND activeDid IS NOT NULL AND activeDid != '');
-    `,
+
-  },
-  {
-    name: "004_remove_activeDid_from_settings",
-    sql: `
       -- Remove activeDid column from settings table (moved to active_identity)
       -- Note: SQLite doesn't support DROP COLUMN in older versions
       -- This migration will be skipped if DROP COLUMN is not supported
       -- The activeDid column will remain but won't be used by the application
-      
-      -- Try to drop the activeDid column (works in SQLite 3.35.0+)
       ALTER TABLE settings DROP COLUMN activeDid;
-    `,
+
-  },
-  {
-    name: "005_eliminate_master_settings_key",
-    sql: `
       -- Eliminate MASTER_SETTINGS_KEY concept - remove confusing id=1 row
       -- This creates clean separation: active_identity for current identity, settings for identity config
-      
-      -- Delete the confusing MASTER_SETTINGS_KEY row (id=1 with accountDid=NULL)
       DELETE FROM settings WHERE id = 1 AND accountDid IS NULL;
       
       -- Reset auto-increment to start from 1 again
       DELETE FROM sqlite_sequence WHERE name = 'settings';
-    `,
+
-  },
-  {
-    name: "006_add_unique_constraint_accountDid",
-    sql: `
       -- Add unique constraint to prevent duplicate accountDid values
       -- This ensures data integrity: each identity can only have one settings record
-      
-      -- First, remove any duplicate accountDid entries (keep the most recent one)
       DELETE FROM settings 
       WHERE id NOT IN (
         SELECT MAX(id) 
@@ -192,7 +183,6 @@ const MIGRATIONS = [
         GROUP BY accountDid
       ) AND accountDid IS NOT NULL;
       
-      -- Add unique constraint on accountDid
       CREATE UNIQUE INDEX IF NOT EXISTS idx_settings_accountDid_unique ON settings(accountDid);
     `,
   },