feat(go-services): Phase 2 ingest — shared Ingestor + shadow consumer

Implements the plugin event handlers (the /ws/position write logic) as a shared
Ingestor, validated against real traffic by replaying Python's /ws/live firehose
into an isolated dereth_go DB (no production write, no plugin stolen).

- ingest.go: faithful ports of telemetry (kill-delta -> char_stats, server
  received_at stamp), rare (rare_stats/rare_stats_sessions/rare_events), portal
  (coord upsert), character_stats (stats_data JSONB subset + upsert), spawn, and
  the memory-only handlers (vitals/quest/equipment_cantrip/nearby/dungeon). In
  -memory live state + read-side overlay accessors.
- shadow.go: coder/websocket consumer of /ws/live -> Ingestor.dispatch (telemetry
  matched by shape since its broadcast has no type field).
- main.go/store.go: ingest mode (READ_ONLY=false + SHADOW_INGEST_WS) wires the
  ingestor; read handlers (/character-stats, /equipment-cantrip, /quest-status)
  now consult the live overlay first, like Python.
- compose: shadow instance ingests ws://dereth-tracker:8765/ws/live.

Validated live: dereth_go has 73 distinct telemetry chars; shadow /live online
set == production (73=73); character_stats 5/5 exact byte-match (0 mismatch);
char_stats kill-deltas + portals accumulating. compare/compare_ingest.py.

Deferred to next pass: combat_stats (delta/merge), share_*, the /ws/position +
/ws/live servers (for cutover).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

go-services/compare/compare_ingest.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""Validate the Go shadow ingest (dereth_go) against production (dereth).
+
+Run on the server. The shadow tracker replays Python's /ws/live firehose into
+its own dereth_go DB. Absolute counts differ (shadow started fresh; char_stats /
+rare_stats accumulate deltas from connect time), so we validate the paths whose
+writes are FULL upserts/inserts and therefore exactly comparable:
+
+  * character_stats: a full-payload upsert. For a character whose row has the
+    SAME timestamp in both DBs, stats_data must be byte-identical.
+  * /live online set: telemetry end-to-end (compared separately by the caller).
+"""
+import json
+import subprocess
+
+SEP = "\x1f"
+
+
+def q(container, db, sql):
+    out = subprocess.check_output(
+        ["docker", "exec", container, "psql", "-U", "postgres", "-d", db, "-tA", "-F", SEP, "-c", sql],
+        text=True)
+    return [line.split(SEP) for line in out.splitlines() if line.strip()]
+
+
+def main():
+    print("=== dereth_go ingested row counts ===")
+    counts = q("dereth-go-db", "dereth_go", """
+        SELECT 'telemetry_events', count(*)::text FROM telemetry_events
+        UNION ALL SELECT 'telemetry_distinct_chars', count(distinct character_name)::text FROM telemetry_events
+        UNION ALL SELECT 'character_stats', count(*)::text FROM character_stats
+        UNION ALL SELECT 'char_stats', count(*)::text FROM char_stats
+        UNION ALL SELECT 'rare_events', count(*)::text FROM rare_events
+        UNION ALL SELECT 'rare_stats', count(*)::text FROM rare_stats
+        UNION ALL SELECT 'portals', count(*)::text FROM portals
+    """)
+    for k, v in counts:
+        print(f"  {k:26} {v}")
+
+    print("\n=== character_stats exact match (same-timestamp rows) ===")
+    prod = {r[0]: (r[1], r[2]) for r in
+            q("dereth-db", "dereth", "SELECT character_name, timestamp::text, stats_data::text FROM character_stats")}
+    shadow = q("dereth-go-db", "dereth_go",
+               "SELECT character_name, timestamp::text, stats_data::text FROM character_stats")
+    match = mismatch = newer = 0
+    for name, ts, sd in shadow:
+        if name not in prod:
+            continue
+        pts, psd = prod[name]
+        if ts != pts:
+            newer += 1  # one side got a newer character_stats message; not comparable
+            continue
+        if json.loads(sd) == json.loads(psd):
+            match += 1
+        else:
+            mismatch += 1
+            print(f"  MISMATCH {name}")
+    print(f"  exact match={match}  mismatch={mismatch}  skipped(diff timestamp)={newer}")
+    print("\nRESULT:", "ingest OK" if mismatch == 0 else f"{mismatch} character_stats mismatch(es)")
+    return 1 if mismatch else 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())