feat: scaffold agentmon services and k8s deploy

Adds Go microservices (ingest-gateway, event-processor, query-api, web-ui), NATS+Postgres wiring, initial schema/init job, ingress manifests for LAN+tailnet, and a multi-arch image build script.

internal/store/postgres/events.go

@@ -0,0 +1,57 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"time"
+)
+
+type InsertEvent struct {
+	EventID string
+	TS      time.Time
+	Type    string
+
+	SessionID    sql.NullString
+	RunID        sql.NullString
+	TraceID      sql.NullString
+	SpanID       sql.NullString
+	ParentSpanID sql.NullString
+
+	SourceFramework sql.NullString
+	ClientID        sql.NullString
+	Payload         any
+}
+
+func (d *DB) InsertEvent(ctx context.Context, e InsertEvent) error {
+	payload, err := json.Marshal(e.Payload)
+	if err != nil {
+		return err
+	}
+
+	_, err = d.sql.ExecContext(ctx, `
+insert into events (
+  event_id, ts, type, session_id, run_id, trace_id, span_id, parent_span_id,
+  source_framework, client_id, payload
+) values (
+  $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11
+)
+on conflict (event_id) do nothing
+`,
+		e.EventID,
+		e.TS,
+		e.Type,
+		e.SessionID,
+		e.RunID,
+		e.TraceID,
+		e.SpanID,
+		e.ParentSpanID,
+		e.SourceFramework,
+		e.ClientID,
+		payload,
+	)
+	return err
+}
+
+var ErrMissingField = errors.New("missing required field")