fix(cli): run plugin discovery before toolset validation

[Linux2010]

Summary

HermesCLI.__init__ called validate_toolset() before discover_plugins(), so plugin-registered toolsets (e.g. beads, spotify) were always flagged as Warning: Unknown toolsets on every startup — even though they worked correctly at runtime.

Root Cause

cli.py:4283-4290 — the validation block queries tools.registry via validate_toolset() → _get_plugin_toolset_names(), but the registry isn't populated with plugin toolsets until discover_plugins() runs. The comment already noted that "discovery hasn't run yet" (referring to MCP), but the same gap applied to plugin-registered toolsets.

Fix

Run discover_plugins() (best-effort, exception-silenced) before the validation block so the tool registry reflects plugin entries.

Live Proof

BEFORE — validate_toolset("spotify") = False
  (spotify plugin not loaded → registry doesn't know it)

AFTER — validate_toolset("spotify") = True
  (discover_plugins() runs first → registry contains spotify tools)

Test run

$ .venv/bin/python -m pytest tests/hermes_cli/test_toolset_validation.py -v
13 passed

Risk

Low. discover_plugins() is idempotent and already called elsewhere during startup. The call is exception-guarded so plugin discovery failure does not block CLI startup.

[alt-glitch]

This was generated by AI during triage.

Duplicate of #29774: both patches address the same CLI ordering defect by discovering plugin toolsets before validation.

[Linux2010]

Closing as duplicate of #29774. Please merge that PR instead.