Bugfix/fix os fam discovery

[graepaul]

Summary

• This PR fixes OS family auto-discover and moves it out of the connection manager into the plugin executor so that it is more transparently sourced.

Test plan

• pytest test/unit
• pytest test/functional (if applicable)
• pre-commit run --all-files

Checklist

• Added/updated tests (or explained why not)
• Updated docs/README if behavior changed
• No secrets or credentials committed

[alexandraBara]

I think we need to enhance our utests here, i ran your branch locally and this is what I get:

node-scraper_public$ node-scraper run-plugins OsPlugin
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Log path: ./scraper_logs_ausalexbara02_2026_09_01-08_15_54_AM
...
  2026-09-01 08:15:54 CDT       INFO               nodescraper | InBandConnectionManager not available or failed to connect for OS discovery. Skipping OS discovery.
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Initializing connection manager for InBandConnectionManager
  2026-09-01 08:15:54 CDT       INFO               nodescraper | --------------------------------------------------
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Running plugin OsPlugin
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Initializing connection: InBandConnectionManager
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Using local shell
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Closing connections
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Running result collators
  2026-09-01 08:15:54 CDT       INFO               nodescraper | Running TableSummary result collator
  2026-09-01 08:15:54 CDT       INFO               nodescraper |

+-------------------------+--------+-----------------------------+
| Connection              | Status | Message                     |
+-------------------------+--------+-----------------------------+
| InBandConnectionManager | OK     | task completed successfully |
+-------------------------+--------+-----------------------------+

+----------+---------+----------------------+
| Plugin   | Status  | Message              |
+----------+---------+----------------------+
| OsPlugin | NOT_RAN | Plugin tasks not ran |
+----------+---------+----------------------+

but your branch passes so this failure is not being caught in functional/utests. Please enhance those as well so we can catch this failure in tests next time.