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")

internal/store/postgres/postgres.go

@@ -0,0 +1,27 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	_ "github.com/jackc/pgx/v5/stdlib"
+)
+
+type DB struct {
+	sql *sql.DB
+}
+
+func Open(url string) (*DB, error) {
+	db, err := sql.Open("pgx", url)
+	if err != nil {
+		return nil, err
+	}
+	return &DB{sql: db}, nil
+}
+
+func (d *DB) Close() error {
+	return d.sql.Close()
+}
+
+func (d *DB) Ping(ctx context.Context) error {
+	return d.sql.PingContext(ctx)
+}

internal/store/postgres/query.go

@@ -0,0 +1,47 @@
+package postgres
+
+import (
+	"context"
+	"encoding/json"
+	"time"
+)
+
+type EventRow struct {
+	EventID string          `json:"event_id"`
+	TS      time.Time       `json:"ts"`
+	Type    string          `json:"type"`
+	Payload json.RawMessage `json:"payload"`
+}
+
+func (d *DB) ListRecentEvents(ctx context.Context, limit int) ([]EventRow, error) {
+	if limit <= 0 {
+		limit = 100
+	}
+	if limit > 1000 {
+		limit = 1000
+	}
+
+	rows, err := d.sql.QueryContext(ctx, `
+select event_id, ts, type, payload
+from events
+order by ts desc
+limit $1
+`, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var out []EventRow
+	for rows.Next() {
+		var r EventRow
+		if err := rows.Scan(&r.EventID, &r.TS, &r.Type, &r.Payload); err != nil {
+			return nil, err
+		}
+		out = append(out, r)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return out, nil
+}