DX-2186: Add Redis stream commands

[CahidArda]

todo:

• fix skipped tests
• improve response formating

fixes #65

[linear]

DX-2186 redis-py - add stream commands

[Copilot]

Pull Request Overview

Adds Redis Streams support to the SDK, including sync/async command implementations, response formatters, type stubs, documentation, and tests. Also bumps the package version.

• Implements XADD, XACK, XDEL, XGROUP, XINFO, XLEN, XPENDING, XRANGE, XREAD, XREADGROUP, XREVRANGE, XTRIM, XCLAIM, XAUTOCLAIM in commands.py
• Adds response formatters and registers stream commands in format.py
• Introduces extensive sync/async tests and updates README; bumps version to 1.5.0

Reviewed Changes

Copilot reviewed 28 out of 29 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
upstash_redis/commands.py	Adds full Redis Streams command implementations (sync)
upstash_redis/commands.pyi	Adds type stubs for new stream commands (sync/async)
upstash_redis/format.py	Adds formatters and registers stream response handlers
tests/... (multiple)	Adds comprehensive sync/async tests for all stream commands
README.md	Documents Streams usage (sync and async)
upstash_redis/init.py	Bumps version to 1.5.0
pyproject.toml	Bumps package version to 1.5.0
tests/commands/asyncio/scripting/test_evalsha_ro.py	Uses client’s script_load for consistency
.github/instructions/project-layout.instructions.md	Adds internal contributor guide for adding commands

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[Copilot]

The formatter converts the "OK" response for XGROUP CREATE and XGROUP SETID to boolean, but the test suite expects the literal "OK" string. Remove these mappings (or map them to a passthrough formatter) so the raw "OK" is returned.