Fix lambda captures and exception handling in HCS static initialization

[Copilot]

Summary of the Pull Request

Addresses code review feedback on PR #13971 by fixing lambda capture lists and improving exception handling in GetProcessorFeatures() and GetSchemaVersion().

PR Checklist

• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated if needed and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated if needed
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Lambda capture fix: Changed [&] to [] in both functions. The lambdas don't capture any variables from the enclosing scope - they only modify static variables which are directly accessible without capture.

Exception handling improvement: Changed static cached values from direct types to std::optional<T>:

• std::vector<std::string> → std::optional<std::vector<std::string>>
• std::pair<uint32_t, uint32_t> → std::optional<std::pair<uint32_t, uint32_t>>

Return statements now use .value() to explicitly unwrap the optional. This makes initialization state unambiguous: if std::call_once completes successfully, the optional is set; if it throws, execution never reaches the return statement.

static std::optional<std::vector<std::string>> g_processorFeatures;
static std::once_flag flag;
std::call_once(flag, []() {
    // ... initialization code that may throw ...
    g_processorFeatures = std::move(response.Response.ProcessorFeatures);
});
return g_processorFeatures.value();  // Only reached if initialization succeeded

Validation Steps Performed

• Code formatting validated with clang-format
• Code review completed with no issues
• CodeQL security scan passed

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