[IC-705] Optimize socket and audio handling

[tmiw]

Performs several optimizations to reduce the CPU usage required for IC-705 support:

1. Use non-blocking sockets instead of select() (similar to what was previously done in #33 for FlexRadio support).
2. Use fixed-point math to amplify TX audio going to the IC-705 (to take advantage of integer-only SIMD instructions on the ESP32-S3 and slightly reduce stack consumption).

Benchmark results:

1.0.3 RX:

| Task | Run Time | Percentage
| IcomSocketTask/ | 119517 | 5%
| IcomSocketTask/ | 121203 | 6%
| IcomSocketTask/ | 57806 | 2%

1.0.3 TX:

| Task | Run Time | Percentage
| IcomSocketTask/ | 142365 | 7%
| IcomSocketTask/ | 59905 | 2%
| IcomSocketTask/ | 97499 | 4%

PR RX:

| Task | Run Time | Percentage
| IcomSocketTask/ | 16438 | 0%
| IcomSocketTask/ | 35090 | 1%
| IcomSocketTask/ | 25191 | 1%

PR TX:

| Task | Run Time | Percentage
| IcomSocketTask/ | 23805 | 1%
| IcomSocketTask/ | 50360 | 2%
| IcomSocketTask/ | 18416 | 0%

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Before merging:

• [x] All CI actions must build without errors.
• [x] If the PR adds new user-facing functionality, this must be documented in the user guide. The Markdown files in the manual folder should be modified for this purpose.