refactor: move --proxy-logs-dir, --audit-dir, --docker-host-path-prefix to AWF config

Move CLI flags that AWF already supports in its config schema into the
JSON config file instead of passing them as CLI arguments:

- logging.proxyLogsDir replaces --proxy-logs-dir (static path)
- logging.auditDir replaces --audit-dir (static path)
- container.dockerHostPathPrefix set when runner.topology is arc-dind

For ARC/DinD, --proxy-logs-dir and --audit-dir CLI flags remain as
runtime overrides because they use ${RUNNER_TEMP} paths that require
shell expansion (CLI overrides config per AWF precedence rules).

The --mount and --container-workdir flags remain as CLI arguments since
--mount requires gh-aw-firewall#5754 and --container-workdir needs
runtime shell variable expansion.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: lpcox