phase 4: hermes agent — MCP tools, activity logging, 'all' role, wiring fixes

- mcp/server.go: 7 new tools (get_signal_history, get_patterns, get_skills,
  request_execution, get_trend, get_event_timeline, get_agent_activity),
  agent_activity logging middleware on every tool call.
- phase3.go: QueryAgentActivity REST handler implemented (was stub).
  Fixed scan count mismatch in ListSkills/PatchSkill/ListSkillVersions
  (13 cols → 12 targets). Fixed AgentActivity cursor pagination
  (lexicographic → integer comparison). Fixed s.Slug → s.Name in log.
- cmd/oikos/main.go: 'all' role now runs api + scheduler + notifier in
  one process. Replaced nil SchedulerRunner/NotifierRunner with direct
  scheduler.RunnerForMain() / notifier.RunnerForMain() imports.
  Added runWithPool helper for standalone scheduler/notifier roles.
- internal/config/config.go: added HermesAgentID env var.
- internal/httpapi/server.go: pass HermesAgentID to MCP handler.
- docker-compose.yml: added scheduler and notifier services (dev profile).
- hermes/: config.yaml, SOUL.md, skills/homelab-ops/SKILL.md.
- Cleaned up: scheduler/init.go dead code, mcp/server.go pgx import guard.

internal/config/config.go

@@ -53,6 +53,9 @@ type Config struct {
 
 	// Approval HMAC secret (Phase 3)
 	ApprovalHMACSecret string
+
+	// Hermes agent entity ID (Phase 4)
+	HermesAgentID string
 }
 
 // Default returns a Config with compiled defaults.
@@ -139,6 +142,9 @@ func FromEnv() Config {
 	if v := os.Getenv("OIKOS_APPROVAL_HMAC_SECRET"); v != "" {
 		c.ApprovalHMACSecret = v
 	}
+	if v := os.Getenv("OIKOS_HERMES_AGENT_ID"); v != "" {
+		c.HermesAgentID = v
+	}
 
 	return c
 }