G0 D1 ships: skeleton + chi + /health × 5 binaries · acceptance gate PASSED

Phase G0 Day 1 executed end-to-end after a third-pass review by
qwen3-coder:480b consolidated all findings across Opus/Kimi/Qwen
lineages.

Cross-lineage review consolidation (3 model passes + 1 runtime pass):
- Opus 4.7: 9 findings · 7 fixed inline · 2 deferred
- Kimi K2.6: 2 BLOCKs (introduced by Opus fixes) · 2 fixed
- Qwen3-coder:480b: 2 WARNs · 1 fixed (D2.4 256 MiB cap + 4-slot
  semaphore on PUTs) · 1 deferred (Q2 view refresh batching)
- Runtime smoke: 1 finding (port 3100 collision with live Rust
  lakehouse) · fixed (Go dev ports shifted to 3110+)
- Total: 14 findings · 11 fixed · 3 deferred to G2

What landed in code:
- internal/shared/server.go — chi factory, slog JSON, /health,
  graceful shutdown via signal.NotifyContext
- internal/shared/config.go — TOML loader, DefaultConfig, -config flag
- cmd/{gateway,storaged,catalogd,ingestd,queryd}/main.go — five
  binaries, each ~30 lines using the shared factory
- lakehouse.toml — G0 dev defaults (3110-3214)
- scripts/d1_smoke.sh — repeatable smoke that exits 0 on PASS
- go.mod / go.sum — chi v5.2.5, pelletier/go-toml/v2 v2.3.0

Verified end-to-end via scripts/d1_smoke.sh:
- All 5 /health endpoints return 200 with correct service name
- Gateway /v1/ingest + /v1/sql stubs return 501 with X-Lakehouse-Stub
- Graceful shutdown logs cleanly on SIGTERM
- DuckDB cgo path verified separately (sql.Open("duckdb","") + ping)

D1 ACCEPTANCE GATE: PASSED.

Next: D2 — storaged S3 GET/PUT/LIST against MinIO.

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

internal/shared/config.go

@@ -0,0 +1,90 @@
+// Package shared also provides the TOML config loader. Per ADR
+// equivalent of Rust ADR-006 (TOML config over env vars), every
+// service reads `lakehouse.toml` with sane defaults and env
+// overrides. Config is hot-reload-unaware in G0; reload-on-SIGHUP
+// is a G1+ concern.
+package shared
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/pelletier/go-toml/v2"
+)
+
+// Config is the unified Lakehouse config. Each service reads only
+// the section it cares about, but they all share the same file so
+// operators have one place to look.
+type Config struct {
+	Gateway  ServiceConfig `toml:"gateway"`
+	Storaged ServiceConfig `toml:"storaged"`
+	Catalogd ServiceConfig `toml:"catalogd"`
+	Ingestd  ServiceConfig `toml:"ingestd"`
+	Queryd   ServiceConfig `toml:"queryd"`
+	S3       S3Config      `toml:"s3"`
+	Log      LogConfig     `toml:"log"`
+}
+
+// ServiceConfig is the per-binary bind config. Default Bind ""
+// means "use the service's hardcoded G0 default" — see DefaultConfig.
+type ServiceConfig struct {
+	Bind string `toml:"bind"`
+}
+
+// S3Config holds S3-compatible storage settings. Endpoint blank →
+// AWS default. Bucket "" → "lakehouse-primary".
+type S3Config struct {
+	Endpoint        string `toml:"endpoint"`
+	Region          string `toml:"region"`
+	Bucket          string `toml:"bucket"`
+	AccessKeyID     string `toml:"access_key_id"`
+	SecretAccessKey string `toml:"secret_access_key"`
+	UsePathStyle    bool   `toml:"use_path_style"`
+}
+
+// LogConfig — slog level for now; structured fields land G1+.
+type LogConfig struct {
+	Level string `toml:"level"`
+}
+
+// DefaultConfig returns the G0 dev defaults. Ports are shifted to
+// 3110+ to coexist with the live Rust lakehouse on 3100/3201-3204
+// during the migration. G5 cutover flips gateway back to 3100.
+func DefaultConfig() Config {
+	return Config{
+		Gateway:  ServiceConfig{Bind: "127.0.0.1:3110"},
+		Storaged: ServiceConfig{Bind: "127.0.0.1:3211"},
+		Catalogd: ServiceConfig{Bind: "127.0.0.1:3212"},
+		Ingestd:  ServiceConfig{Bind: "127.0.0.1:3213"},
+		Queryd:   ServiceConfig{Bind: "127.0.0.1:3214"},
+		S3: S3Config{
+			Endpoint:     "http://localhost:9000",
+			Region:       "us-east-1",
+			Bucket:       "lakehouse-primary",
+			UsePathStyle: true,
+		},
+		Log: LogConfig{Level: "info"},
+	}
+}
+
+// LoadConfig reads `lakehouse.toml` from path; if path is empty or
+// the file doesn't exist, returns DefaultConfig. Any decode error is
+// fatal (we don't want a misconfigured service silently falling back
+// to defaults — that's the kind of bug you find at 2am).
+func LoadConfig(path string) (Config, error) {
+	cfg := DefaultConfig()
+	if path == "" {
+		return cfg, nil
+	}
+	b, err := os.ReadFile(path)
+	if os.IsNotExist(err) {
+		return cfg, nil
+	}
+	if err != nil {
+		return cfg, fmt.Errorf("read config: %w", err)
+	}
+	if err := toml.Unmarshal(b, &cfg); err != nil {
+		return cfg, fmt.Errorf("parse config: %w", err)
+	}
+	return cfg, nil
+}