feat: log the game's high-score report as a gameplay event

When the game builds its high-score table report for Stern's agent
(/api/v1/game/high_score_events - the endpoint the Insider gate already sits
on), the logger writes an HSTD line with all four players' scores. This is
the report the game sends when a game has changed the table, so the line
marks a high-score event with no new per-game RE. The entries themselves
(initials, position) live deeper in the report body and stay uncaptured for
now - that needs locating the report builder or the in-memory table.

Tests: the endpoint trigger and the HSTD line lift into the host harness
(the endpoint pointer is a 32-bit register, so the harness maps its string
below 4 GiB and the tests run on the Linux leg like the port-gate ones).

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

README.md

@@ -20,6 +20,7 @@ why, and the game runs stock.
 | Stock modes (`gamelog: MODE START/END`): the game's own 22 modes with score delta | **deployed on the machine, verified in play** (`mode_score` is approximate) |
 | Award screens (`AWARD id=…`): every award the game shows, extra-ball tracking | **deployed on the machine, verified in play** — except the extra-ball award id is not yet confirmed (below) |
 | Switch/button log (`/dump/switch.log`, `SW` lines with generated names) | **deployed on the machine, verified in play** (flippers on both edges; sites located with `portswitch.switch_source` and added to the port) |
+| High-score reports (`HSTD`): the game's own high-score table report, with all players' scores | **built, deploy pending** — fires when the game sends `/api/v1/game/high_score_events` to Stern's agent; the entries (initials) need new per-game RE (below) |
 
 The machine currently runs the v3 build (events, shots, modes, awards, switch
 log). The v3 work needed more than a rebuild: the port had no `switch_edge` /
@@ -90,6 +91,7 @@ reboots:
 [pad] gamelog: 2026-10-12T20:45:12.123Z MODE END 5 (Island Scene Escape the Swamp) player=1 score=... mode_score=... dur=...ms
 [GAMELOG] 2026-10-12T20:45:12.123Z AWARD EXTRA BALL (id=13) player=1              <- next ball logs as "ball N (EXTRA BALL)"
 [GAMELOG] 2026-10-12T20:45:12.123Z AWARD id=<n> player=1 score=...                <- every award screen
+[GAMELOG] 2026-10-12T20:45:12.123Z HSTD high-score report - P1=95,421,190 P2=0 P3=0 P4=0
 ```
 
 Bus event ids (King Kong 0.97): `game_start`=0x4d, `ball_start`=0x25,