fix: handle numeric JSON Code/value from Gen2 Miniservers in all commands

[discostu105]

Summary

• The Gen2 numeric JSON fix (14d6e45) only covered xml_attr, otel.rs, and commands/system.rs — but 10 other code paths still used .as_str() on parsed JSON LL/Code and LL/value fields, which returns None when Gen2 sends numeric values (e.g. "Code": 200 instead of "Code": "200")
• Adds json_val_str() helper that handles string, integer, and float JSON values uniformly, applied across all affected locations
• Fixes print_resp, cmd_input set, cmd_set, token check/refresh/revoke, and the entire token auth WebSocket flow (keyexchange, gettoken, ws_read_json_value)

Test plan

• cargo fmt --check passes
• cargo clippy -- -D warnings passes
• cargo build --release succeeds
• cargo test — all 292 tests pass (199 unit + 93 integration)
• 5 new tests: json_val_str string/integer/float/null + print_resp with numeric Code
• Manual test against Gen2 Miniserver: lox on, lox input set, lox token check

https://claude.ai/code/session_01GkGQALMGgpih96DkihUEx5

[codecov]

Codecov Report

❌ Patch coverage is 25.00000% with 27 lines in your changes missing coverage. Please review.
✅ Project coverage is 25.12%. Comparing base (9e86192) to head (7edb4f4).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/token.rs	0.00%	15 Missing ⚠️
src/commands/config_cmd.rs	0.00%	8 Missing ⚠️
src/commands/control.rs	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #99      +/-   ##
==========================================
+ Coverage   24.93%   25.12%   +0.19%     
==========================================
  Files          16       16              
  Lines        4656     4672      +16     
==========================================
+ Hits         1161     1174      +13     
- Misses       3495     3498       +3     

Files with missing lines	Coverage Δ
src/main.rs	47.28% <100.00%> (+2.32%)	⬆️
src/commands/control.rs	1.45% <0.00%> (ø)
src/commands/config_cmd.rs	0.00% <0.00%> (ø)
src/token.rs	7.74% <0.00%> (-0.48%)	⬇️

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