feat(migrate): [1/6] core executor, reliability layer, and basic CLI

Adds the migration executor and CLI subcommands for plan/apply/validate:
- executor.py: MigrationExecutor with sync apply, key enumeration, index drop/create, quantization, field/key rename
- reliability.py: BatchUndoBuffer, QuantizationCheckpoint, BGSAVE helpers
- cli/migrate.py: CLI with plan, apply, validate, list, helper, estimate subcommands
- cli/main.py: register migrate command
- cli/utils.py: add_redis_connection_options helper
- Integration tests for comprehensive migration, v1, routes, and field modifier ordering

Author: nkanu17

redisvl/cli/main.py

@@ -2,6 +2,7 @@
 import sys
 
 from redisvl.cli.index import Index
+from redisvl.cli.migrate import Migrate
 from redisvl.cli.stats import Stats
 from redisvl.cli.version import Version
 from redisvl.utils.log import get_logger
@@ -14,6 +15,7 @@ def _usage():
         "rvl <command> [<args>]\n",
         "Commands:",
         "\tindex       Index manipulation (create, delete, etc.)",
+        "\tmigrate     Index migration (plan, apply, validate)",
         "\tversion     Obtain the version of RedisVL",
         "\tstats       Obtain statistics about an index",
     ]
@@ -46,6 +48,10 @@ def version(self):
         Version()
         exit(0)
 
+    def migrate(self):
+        Migrate()
+        exit(0)
+
     def stats(self):
         Stats()
         exit(0)