Add Alembic for database migrations and initial migration scripts

- Created alembic.ini configuration file for Alembic migrations.
- Added README file for Alembic with a brief description.
- Implemented env.py for Alembic to manage database migrations.
- Created script.py.mako template for migration scripts.
- Added initial migration script to create database tables.
- Created a migration script to add initial plan and playlist data.
- Updated database initialization to run Alembic migrations.
- Enhanced credit service to automatically recharge user credits based on their plan.
- Implemented delete_task method in scheduler service to remove scheduled tasks.
- Updated scheduler API to reflect task deletion instead of cancellation.
- Added CLI tool for managing database migrations.
- Updated tests to cover new functionality for task deletion and credit recharge.
- Updated pyproject.toml and lock files to include Alembic as a dependency.

uv.lock

@@ -14,6 +14,20 @@ wheels = [
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 ]
 
+[[package]]
+name = "alembic"
+version = "1.16.5"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "mako" },
+    { name = "sqlalchemy" },
+    { name = "typing-extensions" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/9a/ca/4dc52902cf3491892d464f5265a81e9dff094692c8a049a3ed6a05fe7ee8/alembic-1.16.5.tar.gz", hash = "sha256:a88bb7f6e513bd4301ecf4c7f2206fe93f9913f9b48dac3b78babde2d6fe765e", size = 1969868 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/39/4a/4c61d4c84cfd9befb6fa08a702535b27b21fff08c946bc2f6139decbf7f7/alembic-1.16.5-py3-none-any.whl", hash = "sha256:e845dfe090c5ffa7b92593ae6687c5cb1a101e91fa53868497dbd79847f9dbe3", size = 247355 },
+]
+
 [[package]]
 name = "annotated-types"
 version = "0.7.0"
@@ -465,6 +479,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/62/a1/3d680cbfd5f4b8f15abc1d571870c5fc3e594bb582bc3b64ea099db13e56/jinja2-3.1.6-py3-none-any.whl", hash = "sha256:85ece4451f492d0c13c5dd7c13a64681a86afae63a5f347908daf103ce6d2f67", size = 134899 },
 ]
 
+[[package]]
+name = "mako"
+version = "1.3.10"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "markupsafe" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/9e/38/bd5b78a920a64d708fe6bc8e0a2c075e1389d53bef8413725c63ba041535/mako-1.3.10.tar.gz", hash = "sha256:99579a6f39583fa7e5630a28c3c1f440e4e97a414b80372649c0ce338da2ea28", size = 392474 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/87/fb/99f81ac72ae23375f22b7afdb7642aba97c00a713c217124420147681a2f/mako-1.3.10-py3-none-any.whl", hash = "sha256:baef24a52fc4fc514a0887ac600f9f1cff3d82c61d4d700a1fa84d597b88db59", size = 78509 },
+]
+
 [[package]]
 name = "markdown-it-py"
 version = "3.0.0"
@@ -959,6 +985,7 @@ version = "2.0.0"
 source = { virtual = "." }
 dependencies = [
     { name = "aiosqlite" },
+    { name = "alembic" },
     { name = "apscheduler" },
     { name = "asyncpg" },
     { name = "bcrypt" },
@@ -991,6 +1018,7 @@ dev = [
 [package.metadata]
 requires-dist = [
     { name = "aiosqlite", specifier = "==0.21.0" },
+    { name = "alembic", specifier = "==1.16.5" },
     { name = "apscheduler", specifier = "==3.11.0" },
     { name = "asyncpg", specifier = "==0.30.0" },
     { name = "bcrypt", specifier = "==4.3.0" },