Add CopyFrom methods to GenericArrayView for C++ container support

[Copilot]

Adds the ability to copy data to an Emboss array from C++ containers like std::vector or std::array.

Changes

• CopyFrom: Copies from another GenericArrayView or any iterable C++ container
• UncheckedCopyFrom: Same as above without bounds/validity checks
• TryToCopyFrom: Returns false on size mismatch or element write failure

Uses SFINAE to disambiguate between view and container overloads.

Example

std::uint8_t bytes[4] = {0};
auto array_view = ArrayView<FixedUIntView<8>, ReadWriteContiguousBuffer, 1>{
    ReadWriteContiguousBuffer{bytes, sizeof bytes}};

// Copy from std::vector
std::vector<uint8_t> source = {1, 2, 3, 4};
array_view.CopyFrom(source);

// Copy from std::array
std::array<uint8_t, 4> arr = {{10, 20, 30, 40}};
array_view.CopyFrom(arr);

// Conditional copy (returns false if container too short)
std::vector<uint8_t> short_src = {1, 2};
bool ok = array_view.TryToCopyFrom(short_src);  // false

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• www.googleapis.com
  • Triggering command: /usr/local/lib/node_modules/@bazel/bazelisk/bazelisk-linux_amd64 /usr/local/lib/node_modules/@bazel/bazelisk/bazelisk-linux_amd64 --version (dns block)
  • Triggering command: /usr/local/lib/node_modules/@bazel/bazelisk/bazelisk-linux_amd64 /usr/local/lib/node_modules/@bazel/bazelisk/bazelisk-linux_amd64 version (dns block)
  • Triggering command: /usr/local/lib/node_modules/@bazel/bazelisk/bazelisk-linux_amd64 /usr/local/lib/node_modules/@bazel/bazelisk/bazelisk-linux_amd64 test //runtime/cpp/test:emboss_array_view_test --test_output=errors (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Support Setting an Array from C++ Container</issue_title>
<issue_description>This issue was copied from the upstream repository google/emboss.

Original issue: google#33
Original state: open, created at: 2022-02-15T23:17:13Z, updated at: 2022-02-15T23:19:10Z, by @reventlov

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Original description

It would be convenient to be able to copy to/from an Emboss array from/to a C++ container, such as a std::vector.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Support Setting an Array from C++ Container #85

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