Add self-hosted RCS backend, extension, and ops tooling

Ship the Go/SQLite API and Web UI, Chrome/Brave capture addon,
Docker Compose, Pangolin reverse-proxy support, and a user-crontab
watchdog so the binary stays running without systemd.

scripts/prune-dev-data.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+# Remove local seed/test rows from data/rcs.db; keep real Reddit captures.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+DB="${RCS_DB_PATH:-$ROOT/data/rcs.db}"
+SHOT_DIR="${RCS_DATA_DIR:-$ROOT/data}/screenshots"
+
+if [[ ! -f "$DB" ]]; then
+  echo "No database at $DB — nothing to prune."
+  exit 0
+fi
+
+before="$(sqlite3 "$DB" 'SELECT COUNT(*) FROM comments;')"
+
+sqlite3 "$DB" <<'SQL'
+PRAGMA foreign_keys = ON;
+
+DELETE FROM comments
+WHERE reddit_comment_id = 't1_testcomment1'
+   OR reddit_comment_id LIKE 't1_page_%';
+
+DELETE FROM posts
+WHERE reddit_post_id IN ('t3_testpost1', 't3_onlypost', 't3_seedpost');
+
+DELETE FROM users
+WHERE reddit_user_id IN ('t2_user1', 't2_op', 't2_a', 't2_seed');
+
+-- Orphan posts with no comments left
+DELETE FROM posts
+WHERE id NOT IN (SELECT DISTINCT post_id FROM comments);
+
+-- Orphan users not referenced by comments or posts
+DELETE FROM users
+WHERE id NOT IN (SELECT DISTINCT author_id FROM comments)
+  AND id NOT IN (SELECT DISTINCT author_id FROM posts);
+SQL
+
+rm -f "$SHOT_DIR/t1_testcomment1.png"
+
+after="$(sqlite3 "$DB" 'SELECT COUNT(*) FROM comments;')"
+posts="$(sqlite3 "$DB" 'SELECT COUNT(*) FROM posts;')"
+users="$(sqlite3 "$DB" 'SELECT COUNT(*) FROM users;')"
+
+echo "Pruned seed/test data from $DB"
+echo "  comments: $before -> $after"
+echo "  posts:    $posts"
+echo "  users:    $users"