pathwayd: HTTP service over internal/pathway · 11/11 smoke gate

Network-callable Mem0-style trace memory at :3217, fronted by gateway
/v1/pathway/*. Closes the ADR-004 wire-up: store substrate landed in
2a6234f, this lands the HTTP surface + [pathwayd] config + acceptance
gate.

Smoke proves the architecturally distinctive properties: Revise →
History walks the predecessor chain backward (audit trail), Retire
excludes from Search default but stays Get-able, AddIdempotent bumps
replay_count without replacing — and all survive kill+restart via
JSONL log replay.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/shared/config.go

@@ -26,6 +26,7 @@ type Config struct {
 	Queryd   QuerydConfig  `toml:"queryd"`
 	Vectord  VectordConfig `toml:"vectord"`
 	Embedd   EmbeddConfig  `toml:"embedd"`
+	Pathwayd PathwaydConfig `toml:"pathwayd"`
 	S3       S3Config      `toml:"s3"`
 	Log      LogConfig     `toml:"log"`
 	Auth     AuthConfig    `toml:"auth"`
@@ -50,8 +51,8 @@ type IngestConfig struct {
 
 // GatewayConfig adds the upstream URLs the reverse proxy fronts.
 // Each route family (/v1/storage, /v1/catalog, /v1/ingest, /v1/sql,
-// /v1/vectors, /v1/embed) has its own upstream so we can scale
-// services independently or move them to different boxes without
+// /v1/vectors, /v1/embed, /v1/pathway) has its own upstream so we can
+// scale services independently or move them to different boxes without
 // touching gateway code.
 type GatewayConfig struct {
 	Bind        string `toml:"bind"`
@@ -61,6 +62,7 @@ type GatewayConfig struct {
 	QuerydURL   string `toml:"queryd_url"`
 	VectordURL  string `toml:"vectord_url"`
 	EmbeddURL   string `toml:"embedd_url"`
+	PathwaydURL string `toml:"pathwayd_url"`
 }
 
 // EmbeddConfig drives the embed service. ProviderURL points at the
@@ -85,6 +87,15 @@ type VectordConfig struct {
 	StoragedURL string `toml:"storaged_url"`
 }
 
+// PathwaydConfig drives the pathway-memory service (cmd/pathwayd).
+// PersistPath: file path to the JSONL log; empty = in-memory only
+// (test/dev). Production sets a stable path under /var/lib/lakehouse
+// or similar so traces survive restart.
+type PathwaydConfig struct {
+	Bind        string `toml:"bind"`
+	PersistPath string `toml:"persist_path"`
+}
+
 // QuerydConfig adds queryd-specific knobs. queryd talks DuckDB
 // directly to MinIO via DuckDB's httpfs extension (so no storaged
 // URL needed), and reads the catalog over HTTP for view registration.
@@ -161,6 +172,7 @@ func DefaultConfig() Config {
 			QuerydURL:   "http://127.0.0.1:3214",
 			VectordURL:  "http://127.0.0.1:3215",
 			EmbeddURL:   "http://127.0.0.1:3216",
+			PathwaydURL: "http://127.0.0.1:3217",
 		},
 		Storaged: ServiceConfig{Bind: "127.0.0.1:3211"},
 		Catalogd: CatalogConfig{Bind: "127.0.0.1:3212", StoragedURL: "http://127.0.0.1:3211"},
@@ -180,6 +192,11 @@ func DefaultConfig() Config {
 			DefaultModel: "nomic-embed-text",
 			CacheSize:    10_000, // ~30 MiB at d=768; set to 0 to disable
 		},
+		Pathwayd: PathwaydConfig{
+			Bind: "127.0.0.1:3217",
+			// PersistPath empty by default = in-memory only. Production
+			// sets to e.g. /var/lib/lakehouse/pathway/state.jsonl.
+		},
 		Queryd: QuerydConfig{
 			Bind:         "127.0.0.1:3214",
 			CatalogdURL:  "http://127.0.0.1:3212",