feat(cli): replace manual switch with cli.Main + WithCommands

main.go shrinks from 296 lines to 11. All commands register through
Core framework lifecycle via cli.WithCommands. Gets signal handling,
shell completion, grouped help, and TUI primitives.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main.go

@@ -1,128 +1,12 @@
 package main
 
 import (
-	"flag"
-	"fmt"
-	"log"
-	"os"
-
-	"forge.lthn.ai/lthn/lem/pkg/lem"
+	"forge.lthn.ai/core/go/pkg/cli"
+	"forge.lthn.ai/lthn/lem/cmd/lemcmd"
 )
 
-const usage = `Usage: lem <command> [flags]
-
-Scoring:
-  score          Score existing response files
-  probe          Generate responses and score them
-  compare        Compare two score files
-  tier-score     Score expansion responses (heuristic/judge tiers)
-  agent          ROCm scoring daemon (polls M3, scores checkpoints)
-
-Generation:
-  distill        Native Metal distillation (go-mlx + go-i18n grammar scoring)
-  expand         Generate expansion responses via trained LEM model
-  conv           Generate conversational training data (calm phase)
-
-Data Management:
-  import-all     Import ALL LEM data into DuckDB from M3
-  consolidate    Pull worker JSONLs from M3, merge, deduplicate
-  normalize      Normalize seeds → deduplicated expansion_prompts
-  approve        Filter scored expansions → training JSONL
-
-Export & Publish:
-  export         Export golden set to training-format JSONL splits
-  parquet        Export JSONL training splits to Parquet
-  publish        Push Parquet files to HuggingFace dataset repo
-  convert        Convert MLX LoRA adapter to PEFT format
-
-Monitoring:
-  status         Show training and generation progress (InfluxDB)
-  expand-status  Show expansion pipeline status (DuckDB)
-  inventory      Show DuckDB table inventory
-  coverage       Analyze seed coverage gaps
-  metrics        Push DuckDB golden set stats to InfluxDB
-
-Distributed:
-  worker         Run as distributed inference worker node
-
-Infrastructure:
-  ingest         Ingest benchmark data into InfluxDB
-  seed-influx    Seed InfluxDB golden_gen from DuckDB
-  query          Run ad-hoc SQL against DuckDB
-`
-
 func main() {
-	if len(os.Args) < 2 {
-		fmt.Fprint(os.Stderr, usage)
-		os.Exit(1)
-	}
-
-	switch os.Args[1] {
-	case "distill":
-		lem.RunDistill(os.Args[2:])
-	case "score":
-		lem.RunScore(os.Args[2:])
-	case "probe":
-		lem.RunProbe(os.Args[2:])
-	case "compare":
-		fs := flag.NewFlagSet("compare", flag.ExitOnError)
-		oldFile := fs.String("old", "", "Old score file (required)")
-		newFile := fs.String("new", "", "New score file (required)")
-		if err := fs.Parse(os.Args[2:]); err != nil {
-			log.Fatalf("parse flags: %v", err)
-		}
-		if *oldFile == "" || *newFile == "" {
-			fmt.Fprintln(os.Stderr, "error: --old and --new are required")
-			fs.Usage()
-			os.Exit(1)
-		}
-		if err := lem.RunCompare(*oldFile, *newFile); err != nil {
-			log.Fatalf("compare: %v", err)
-		}
-	case "status":
-		lem.RunStatus(os.Args[2:])
-	case "expand":
-		lem.RunExpand(os.Args[2:])
-	case "export":
-		lem.RunExport(os.Args[2:])
-	case "conv":
-		lem.RunConv(os.Args[2:])
-	case "ingest":
-		lem.RunIngest(os.Args[2:])
-	case "parquet":
-		lem.RunParquet(os.Args[2:])
-	case "publish":
-		lem.RunPublish(os.Args[2:])
-	case "metrics":
-		lem.RunMetrics(os.Args[2:])
-	case "convert":
-		lem.RunConvert(os.Args[2:])
-	case "import-all":
-		lem.RunImport(os.Args[2:])
-	case "consolidate":
-		lem.RunConsolidate(os.Args[2:])
-	case "normalize":
-		lem.RunNormalize(os.Args[2:])
-	case "approve":
-		lem.RunApprove(os.Args[2:])
-	case "tier-score":
-		lem.RunTierScore(os.Args[2:])
-	case "expand-status":
-		lem.RunExpandStatus(os.Args[2:])
-	case "inventory":
-		lem.RunInventory(os.Args[2:])
-	case "coverage":
-		lem.RunCoverage(os.Args[2:])
-	case "seed-influx":
-		lem.RunSeedInflux(os.Args[2:])
-	case "query":
-		lem.RunQuery(os.Args[2:])
-	case "agent":
-		lem.RunAgent(os.Args[2:])
-	case "worker":
-		lem.RunWorker(os.Args[2:])
-	default:
-		fmt.Fprintf(os.Stderr, "unknown command: %s\n\n%s", os.Args[1], usage)
-		os.Exit(1)
-	}
+	cli.Main(
+		cli.WithCommands("lem", lemcmd.AddLEMCommands),
+	)
 }