fix(hindsight): clarify pip dependency per mode in README

[ten-ltw]

What does this PR do?

Fixes a documentation gap in plugins/memory/hindsight/README.md — the "Client Version" section implied that hindsight-client is the only required package, but local_embedded mode actually requires hindsight-all.

Changes

plugins/memory/hindsight/README.md:

Before:
```
Requires hindsight-client >= 0.4.22. The plugin auto-upgrades on session start if an older version is detected.
```

After: A dependency table is added:

Mode	Package	Minimum Version
cloud	hindsight-client	>= 0.4.22
local_external	hindsight-client	>= 0.4.22
local_embedded	hindsight-all	>= 0.5.0

With a clear note that hindsight-all is not auto-upgraded, and the install command to fix it.

Related Issue

Partially addresses the documentation concern raised in #7718 (the code fix for #7718 is submitted separately as PR #7745).