Add artifact publication ledger and export pipeline (#1251)

Second PR in the artifact-sync split (follows #1242, which froze the wire format and added the docbank-backed store). Extracted from the closed #1239 branch with review fixes applied during extraction.

## What this adds

- **SQLite publication ledger** (`internal/db`): `artifact_export_queue`, `artifact_publications`, `artifact_publication_revisions`, `artifact_checkpoint_heads`/`_floors`, plus session triggers that enqueue owned-session changes. Triggers are origin-gated — they fire only once an artifact origin exists in `pg_sync_state` — so archives that never opt in carry no queue writes. Trigger DDL lives in Go and is installed after column migrations (drops run before), so no trigger references session columns while migrations run.
- **Go enqueue hooks** for child-only mutations that don't touch trigger-covered session columns: batch message writes (queue generation sampled around the batch, enqueues exactly once when the triggers didn't fire), standalone usage-event replacement, and token-coverage backfill. Queue bootstrap is an explicit call at origin creation, not a migrate-time backfill.
- **Origin lifecycle** (`internal/artifact`): `EnsureOrigin`/`AdoptOrigin`/`StoredOrigin`. Creating or adopting an origin bootstraps the export queue; a failed bootstrap rolls the origin back (deleting the key when there was none before, since the gates test key existence) so a retry re-runs population. Adopting over a different established origin force-requeues every owned session with a generation bump, because prior acknowledgements belong to the old origin.
- **Checkpointed export pipeline** (`internal/artifact`): claims pending queue rows, publishes content-addressed session manifests and segments into the store, records publication revisions, and advances per-origin checkpoint heads with monotone sequence reservation. Stale claims (a writer advanced the generation mid-export) roll back atomically. Incremental export is bounded by the dirty batch; an unchanged archive costs a catalog identity check only. Full export streams all bodies, then re-checks the queue up to 32 settle rounds — hitting the bound returns the accumulated result with an error meaning "made progress, run again."
- **Resync carriage**: `CopySyncStateFrom` carries queue, publication, revision, and checkpoint state across a full resync and re-dirties every copied queue row — the origin gate keeps triggers silent in the rebuild's temp DB, and a parser bump changes manifest hashes anyway, so the exporter must re-verify each session (unchanged content is cheap to skip, being content-addressed).

## Scope and limitations

- Export-side only. Nothing wires the pipeline to the daemon or CLI yet; that lands with folder transport and import in a later PR. There is no import/read path here.
- The ledger is local SQLite state. PostgreSQL push and shared query shapes are untouched.
- The wire format is unchanged: no golden churn, format stays frozen at v1.

## Where to look

- `internal/db/artifact_publication.go` — queue and ledger SQL, origin-gated enqueue
- `internal/db/db.go` — trigger DDL split around column migrations, bootstrap/requeue
- `internal/artifact/export.go` — publish → manifest → checkpoint ordering and claim lifecycle
- `internal/artifact/origin.go` — origin lifecycle and rollback semantics
- `internal/db/orphaned.go` — resync carriage and the pending-flag decision

Co-authored-by: Wes McKinney <wesm@users.noreply.github.com>

Author: wesm

cmd/agentsview/artifact_machine_test.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.kenn.io/agentsview/internal/config"
+	"go.kenn.io/agentsview/internal/db"
+)
+
+func TestOpenDBConfiguresArtifactLocalMachineOwnership(t *testing.T) {
+	cfg := config.Config{
+		DBPath:           filepath.Join(t.TempDir(), "sessions.db"),
+		LocalMachineName: "workstation.example",
+	}
+	database, err := openDB(cfg)
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, database.Close()) })
+	require.NoError(t, database.UpsertSession(db.Session{
+		ID: "hostname-local", Project: "project",
+		Machine: cfg.LocalMachineName, Agent: "claude",
+	}))
+	_, err = database.EnsureArtifactOrigin("desktop-a1b2c3")
+	require.NoError(t, err)
+
+	pending, err := database.PendingArtifactExports(t.Context(), 10)
+	require.NoError(t, err)
+	require.Len(t, pending, 1)
+	assert.Equal(t, "hostname-local", pending[0].SessionID)
+}

cmd/agentsview/main.go

@@ -1235,6 +1235,14 @@ func openDB(cfg config.Config) (*db.DB, error) {
 	if err != nil {
 		return nil, err
 	}
+	localMachine := cfg.LocalMachineName
+	if strings.TrimSpace(localMachine) == "" {
+		localMachine = "local"
+	}
+	if err := database.ConfigureArtifactLocalMachine(localMachine); err != nil {
+		database.Close()
+		return nil, fmt.Errorf("configuring artifact local machine: %w", err)
+	}
 	applyCustomPricing(database, cfg)
 	return database, nil
 }