feat(scrape): offline prove smoke and snapshot-only mode

Add --snapshot-only and --compare-snapshots to prove-incremental-append,
fix EXIT trap status, wire prove smoke into CI, and document LFG closure plan.

.github/workflows/main.yml

@@ -79,6 +79,7 @@ jobs:
           ./scripts/tests/scrape-here-smoke.sh
           ./scripts/tests/bootstrap-recurring-scrape-smoke.sh
           ./scripts/tests/audit-archive-json-smoke.sh
+          ./scripts/tests/prove-incremental-append-smoke.sh
 
   test:
     # Tests need access to secrets, so we can't run them against PRs because of limited trust

docs/plans/2026-05-29-019-feat-lfg-closure-plan.md

@@ -0,0 +1,52 @@
+---
+title: feat: LFG closure — prove smoke and workspace bridge
+type: feat
+status: complete
+date: 2026-05-29
+origin: Repeated /lfg — recurring scrape stack complete; close gaps for operators and CI
+---
+
+# feat: LFG closure — prove smoke and workspace bridge
+
+## Summary
+
+Recurring scrape is feature-complete on `feat/recurring-cli-scrape`. This slice adds an offline prove smoke test, documents audit/salvage in the GUI zip bridge, and refreshes the open PR summary.
+
+## Requirements
+
+| ID | Requirement |
+|----|-------------|
+| R1 | `prove-incremental-append.sh` supports `--snapshot-only` for offline verification |
+| R2 | `scripts/tests/prove-incremental-append-smoke.sh` validates invalid JSON skip + grow-only compare |
+| R3 | CI `recurring-scrape-smoke` job runs prove smoke |
+| R4 | `DiscordChatExporter.linux-x64/RECURRING-SCRAPE.md` mentions audit/salvage |
+| R5 | PR #1538 body includes plan 018 audit/salvage summary |
+
+## Implementation Units
+
+### U1. Prove snapshot-only mode
+
+**Files:** `scripts/prove-incremental-append.sh`
+
+Add `--snapshot-only` that writes snapshot TSV and exits (no Discord scrape).
+
+### U2. Prove smoke test
+
+**Files:** `scripts/tests/prove-incremental-append-smoke.sh`
+
+Fixture archives: valid JSON, invalid JSON (skipped), then simulate grow-only compare.
+
+### U3. Workspace bridge
+
+**Files:** `../DiscordChatExporter.linux-x64/RECURRING-SCRAPE.md` (sibling path from repo: document in plan as operator copy target — implement via `scripts/sync-workspace-bridge.sh` or direct edit if path exists)
+
+Use repo-relative note: bridge file lives beside repo at `DiscordChatExporter.linux-x64/RECURRING-SCRAPE.md`.
+
+### U4. PR body refresh
+
+Update PR #1538 via `gh pr edit` with Latest section for `a2aeaaa` and plan 019.
+
+## Verification
+
+- `./scripts/tests/prove-incremental-append-smoke.sh`
+- All existing `scripts/tests/*.sh` pass

scripts/prove-incremental-append.sh

@@ -13,6 +13,8 @@ usage() {
   cat <<EOF
 Usage:
   $(basename "$0") --target NAME [--config PATH]
+  $(basename "$0") --target NAME --snapshot-only --snapshot-file PATH [--config PATH]
+  $(basename "$0") --compare-snapshots BEFORE.tsv AFTER.tsv
 
 Record message counts for every JSON archive under the target's output_dir,
 run one incremental scrape, then assert:
@@ -29,7 +31,10 @@ die() {
 }
 
 cleanup() {
-  [[ -n "$SNAPSHOT_DIR" && -d "$SNAPSHOT_DIR" ]] && rm -rf "$SNAPSHOT_DIR"
+  if [[ -n "${SNAPSHOT_DIR:-}" && -d "$SNAPSHOT_DIR" ]]; then
+    rm -rf "$SNAPSHOT_DIR"
+  fi
+  return 0
 }
 
 require_command() {
@@ -110,6 +115,10 @@ compare_snapshots() {
 
 main() {
   local target=""
+  local snapshot_only=0
+  local snapshot_file=""
+  local compare_before=""
+  local compare_after=""
 
   trap cleanup EXIT
 
@@ -125,6 +134,21 @@ main() {
         CONFIG_PATH=$2
         shift 2
         ;;
+      --snapshot-only)
+        snapshot_only=1
+        shift
+        ;;
+      --snapshot-file)
+        [[ $# -ge 2 ]] || die "Missing value for --snapshot-file."
+        snapshot_file=$2
+        shift 2
+        ;;
+      --compare-snapshots)
+        [[ $# -ge 3 ]] || die "Missing paths for --compare-snapshots."
+        compare_before=$2
+        compare_after=$3
+        shift 3
+        ;;
       --help|-h)
         usage
         exit 0
@@ -135,15 +159,32 @@ main() {
     esac
   done
 
+  require_command jq
+
+  if [[ -n "$compare_before" ]]; then
+    [[ -f "$compare_before" ]] || die "Missing snapshot: $compare_before"
+    [[ -f "$compare_after" ]] || die "Missing snapshot: $compare_after"
+    compare_snapshots "$compare_before" "$compare_after"
+    printf 'Snapshot comparison passed.\n'
+    exit 0
+  fi
+
   [[ -n "$target" ]] || die "--target is required."
 
-  require_command jq
   [[ -f "$CONFIG_PATH" ]] || die "Missing config: $CONFIG_PATH"
 
   local output_dir
   output_dir=$(target_output_dir "$target")
   [[ -n "$output_dir" && "$output_dir" != "null" ]] || die "Unknown target: $target"
 
+  if (( snapshot_only )); then
+    [[ -n "$snapshot_file" ]] || die "--snapshot-file is required with --snapshot-only."
+    snapshot_archives "$output_dir" "$snapshot_file"
+    [[ -s "$snapshot_file" ]] || die "No seeded archives found under $output_dir"
+    printf 'Snapshot written: %s\n' "$snapshot_file"
+    exit 0
+  fi
+
   SNAPSHOT_DIR=$(mktemp -d "${TMPDIR:-/tmp}/dce-prove-append.XXXXXX")
   local before_file="$SNAPSHOT_DIR/before.tsv"
   local after_file="$SNAPSHOT_DIR/after.tsv"

scripts/tests/prove-incremental-append-smoke.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+
+set -Eeuo pipefail
+
+REPO_ROOT=$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd -P)
+PROVE="$REPO_ROOT/scripts/prove-incremental-append.sh"
+TMP_DIR=$(mktemp -d "${TMPDIR:-/tmp}/dce-prove-smoke.XXXXXX")
+ARCHIVE_ROOT="$TMP_DIR/archive"
+CONFIG_PATH="$TMP_DIR/config.json"
+BEFORE="$TMP_DIR/before.tsv"
+AFTER="$TMP_DIR/after.tsv"
+
+cleanup() {
+  rm -rf "$TMP_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$ARCHIVE_ROOT/demo"
+
+cat >"$ARCHIVE_ROOT/demo/Guild - general [111111111111111111].json" <<'JSON'
+{
+  "guild": {"id": "1", "name": "Guild"},
+  "channel": {"id": "111111111111111111", "name": "general"},
+  "messages": [
+    {"id": "1", "timestamp": "2020-01-01T00:00:00+00:00", "type": "Default", "content": "one"}
+  ],
+  "messageCount": 1
+}
+JSON
+
+printf '{"messages":[\n' >"$ARCHIVE_ROOT/demo/truncated [222222222222222222].json"
+
+cat >"$CONFIG_PATH" <<JSON
+{
+  "archive_root": "$ARCHIVE_ROOT",
+  "targets": [
+    {
+      "name": "demo",
+      "kind": "guild",
+      "output_dir": "$ARCHIVE_ROOT/demo",
+      "enabled": true
+    }
+  ]
+}
+JSON
+
+DCE_PRIMARY_CONFIG="$CONFIG_PATH" "$PROVE" --target demo --snapshot-only --snapshot-file "$BEFORE"
+
+if ! grep -q '111111111111111111' "$BEFORE"; then
+  printf 'ERROR: snapshot missing valid channel archive\n' >&2
+  exit 1
+fi
+if grep -q '222222222222222222' "$BEFORE"; then
+  printf 'ERROR: invalid JSON file should be skipped in snapshot\n' >&2
+  exit 1
+fi
+
+cat >"$ARCHIVE_ROOT/demo/Guild - general [111111111111111111].json" <<'JSON'
+{
+  "guild": {"id": "1", "name": "Guild"},
+  "channel": {"id": "111111111111111111", "name": "general"},
+  "messages": [
+    {"id": "1", "timestamp": "2020-01-01T00:00:00+00:00", "type": "Default", "content": "one"},
+    {"id": "2", "timestamp": "2020-01-02T00:00:00+00:00", "type": "Default", "content": "two"}
+  ],
+  "messageCount": 2
+}
+JSON
+
+DCE_PRIMARY_CONFIG="$CONFIG_PATH" "$PROVE" --target demo --snapshot-only --snapshot-file "$AFTER"
+"$PROVE" --compare-snapshots "$BEFORE" "$AFTER"
+
+if "$PROVE" --compare-snapshots "$AFTER" "$BEFORE" 2>/dev/null; then
+  printf 'ERROR: shrink comparison should have failed\n' >&2
+  exit 1
+fi
+
+printf 'prove-incremental-append-smoke: ok\n'