notifyr: ntfy send/read client for agents

send (title/priority/tags), read (poll mode, greppable one-liners),
topics (known homelab buses from config). Config with homelab defaults
on first run. Unit tests against httptest; smoked against the real
ntfy on topic agent-tools-test. Spec: doc/tool-parity.md 3.3.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011KikHkfCiC3yELbsMN8fT9

notifyr/notify/config.go

@@ -0,0 +1,78 @@
+package notify
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// Config is ~/.config/notifyr/config.json, created with homelab
+// defaults on first run. NOTIFYR_CONFIG overrides the path.
+type Config struct {
+	Server       string            `json:"server"`
+	Token        string            `json:"token"`
+	DefaultTopic string            `json:"default_topic"`
+	Topics       map[string]string `json:"topics"` // known topics -> what they carry (informational)
+}
+
+func DefaultConfig() *Config {
+	return &Config{
+		Server:       "https://ntfy.brasse-pc.eu",
+		Token:        "",
+		DefaultTopic: "claude",
+		Topics: map[string]string{
+			"claude":           "agents' direct notes to Björn",
+			"agent-helm":       "agent-helm events (question waiting, session died)",
+			"Info":             "*arr system events",
+			"media-hamtningar": "media grabbed for download",
+			"media-nytt":       "new media landed in Jellyfin",
+			"pi5-server":       "server maintenance (reboots, watchtower)",
+			"pi5-server-fel":   "server problems: failed units, disk space",
+			"ci-fel":           "failed Gitea Actions builds",
+			"monitoring":       "Uptime Kuma up/down alerts",
+		},
+	}
+}
+
+func ConfigPath() string {
+	if p := os.Getenv("NOTIFYR_CONFIG"); p != "" {
+		return p
+	}
+	dir, err := os.UserConfigDir()
+	if err != nil {
+		dir = "."
+	}
+	return filepath.Join(dir, "notifyr", "config.json")
+}
+
+// LoadConfig reads the config, creating it with defaults on first run.
+func LoadConfig(path string) (*Config, error) {
+	cfg := DefaultConfig()
+	data, err := os.ReadFile(path)
+	if os.IsNotExist(err) {
+		if err := SaveConfig(path, cfg); err != nil {
+			return nil, err
+		}
+		fmt.Fprintf(os.Stderr, "notifyr: created %s\n", path)
+		return cfg, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	if err := json.Unmarshal(data, cfg); err != nil {
+		return nil, fmt.Errorf("%s: %w", path, err)
+	}
+	return cfg, nil
+}
+
+func SaveConfig(path string, cfg *Config) error {
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		return err
+	}
+	data, err := json.MarshalIndent(cfg, "", "  ")
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(path, append(data, '\n'), 0o600)
+}