Replace grep -P with grep -E to avoid illegal instruction on non-AVX …

[alisaklak]

Summary

grep -P triggers PCRE JIT which depends on AVX CPU instructions. On systems without AVX
(for example many VMware ESXi hosts and older Xeon CPUs), this results in a crash during
Talk relay startup:

Illegal instruction (core dumped)

This prevents the Talk High Performance Backend from running on those environments.

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What this PR changes

Replaces:

grep -oP

with:

grep -oE

in Containers/talk/start.sh.

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Why this works

grep -E uses the POSIX Extended Regular Expression engine, which:

• does not use PCRE JIT
• does not require AVX CPU instructions
• produces identical matching behavior for this pattern

This makes the script compatible with a wider range of hardware.

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Result

Talk relay startup now works correctly on:

• VMware ESXi hosts
• Older Xeon CPUs without AVX

There is:

• No functional behavior change
• No performance impact
• No configuration change required

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Testing

Verified on:

• ESXi 7.0.0 host
• Intel Xeon CPU (no AVX support)
• Nextcloud AIO Talk container starts and runs normally.