fix(config): redirect platforms.<name>.<display_setting> to display.platforms.<name>.<setting> (#71047)

[zoser69]

Summary

Fixes Problem A of #71047: hermes config set platforms.<name>.<display_setting> <value> writes to a key the runtime never reads, so the edit appears to succeed while having no effect.

Root cause: the gateway reads per-platform display settings (streaming, show_reasoning, tool_progress, …) from display.platforms.<name>.<setting> (see gateway/display_config.py::resolve_display_setting), while the top-level platforms.<name> block holds only connection config (token, extra, channel_overrides). set_config_value wrote the dotted path verbatim, so platforms.telegram.streaming landed in the connection block and was silently ignored by the loader.

This mirrors the existing set-time alias/redirect pattern already in set_config_value (model.api_base → model.base_url, bare model → model.default).

Fix

In hermes_cli/config.py::set_config_value, before the write, redirect a platforms.<name>.<setting> key to display.platforms.<name>.<setting> only when <setting> is a known per-platform display setting (gateway.display_config.OVERRIDEABLE_KEYS). Real connection keys (token, extra, channel_overrides, …) are left untouched. The gateway.display_config import is lazy/try-guarded to avoid a circular import (gateway/config.py already imports hermes_cli.config) and to keep the CLI working in minimal installs where gateway is not importable.

Scope

This PR addresses only Problem A (the config-set duplicate/mis-targeted key). Problem B (Telegram streaming resend duplication) is a separate runtime issue and intentionally out of scope here, per the triage recommendation to keep the fix focused.

Test plan

• Added tests/hermes_cli/test_config_set_platforms_redirect.py:
  • platforms.telegram.streaming false → display.platforms.telegram.streaming: false (bool-coerced), and no stray streaming key under the top-level platforms.telegram connection block.
  • platforms.telegram.show_reasoning / platforms.discord.tool_progress redirect correctly.
  • A real connection key (platforms.telegram.token) is not redirected.
  • When no top-level platforms block exists, the redirect does not invent one — it writes only display.platforms....

hermes config set platforms.telegram.streaming false
# (note: per-platform display setting — saved as display.platforms.telegram.streaming)
✓ Set display.platforms.telegram.streaming = False in ~/.hermes/config.yaml

Closes #71047 (Problem A)