Adjust combat stats after playtest 1

Playtest 1 (first two pushes, ~40 min game time — pacing on target)
found the railgun_s-spam-cruiser meta and confirmed the repair tool as
overpowered (second signal after the persistent arena escort margin):

- repair_tool 9 -> 4 HP/s: the arena only prices in-fight sustain; real
  runs add free between-wave top-offs across the whole swarm
- railgun_l range 100 -> 130: now outranges stations (120), buying the
  siege role the capital ladder promises
- railgun_m 14 -> 16 dmg, range 70 -> 80: concentration tax softened so
  the ladder reads "pay some DPS efficiency for reach", not
  "strictly worse"
- new tracked arena: railgun_s-spam cruisers vs default cruisers

Module costs untouched, so all threat values stay valid. Docs updated
(derived.md, history.md playtest record, README status).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DyCu8vwChKMbLJQ3xosYEN

bin/balancing/data/balancing.toml

@@ -4,7 +4,8 @@
 # using the verified fitted threat values from tools/threat_report.py:
 #   drone 10.5, frigate 47, destroyer 99, cruiser 233.5,
 #   battlecruiser 354.5, battleship 722.5, dreadnought 1491.5,
-#   carrier 1436.5, glass destroyer (8 small guns) 92, repair drone 17.
+#   carrier 1436.5, glass destroyer (8 small guns) 92, repair drone 17,
+#   railgun_s-spam cruiser (12 small guns) 178.
 # Module arrays mirror the ships' default_modules loadouts unless a
 # doctrine variant is the point of the arena.
 #
@@ -348,6 +349,50 @@ enemy_buffer_width_tiles = 10
       {type = "railgun_s", x = 4, y = 1, rotation = "east"},
     ]
 
+[[arena]]
+name = "Railgun_s-spam cruisers vs default cruisers (1424 vs 1401)"
+# Tracks the playtest-1 meta: cruiser hulls filled with 12 small guns
+# (max DPS/threat, no armor, range 50) against the default m-gun fit.
+# The concentration tax means the spam side SHOULD win a brawl somewhat;
+# this arena bounds its margin — a blowout here means the small-gun
+# premium or the m-gun range edge needs retuning.
+height_tiles = 10
+player_buffer_width_tiles = 10
+contest_zone_width_tiles = 50
+enemy_buffer_width_tiles = 10
+
+  [[arena.team]]
+  name = "Spam"
+    [[arena.team.ship]]
+    schematic = "cruiser"
+    count = 8
+    modules = [
+      {type = "railgun_s", x = 1, y = 0, rotation = "east"},
+      {type = "railgun_s", x = 2, y = 0, rotation = "east"},
+      {type = "railgun_s", x = 0, y = 1, rotation = "east"},
+      {type = "railgun_s", x = 1, y = 1, rotation = "east"},
+      {type = "railgun_s", x = 2, y = 1, rotation = "east"},
+      {type = "railgun_s", x = 3, y = 1, rotation = "east"},
+      {type = "railgun_s", x = 0, y = 2, rotation = "east"},
+      {type = "railgun_s", x = 1, y = 2, rotation = "east"},
+      {type = "railgun_s", x = 2, y = 2, rotation = "east"},
+      {type = "railgun_s", x = 3, y = 2, rotation = "east"},
+      {type = "railgun_s", x = 1, y = 3, rotation = "east"},
+      {type = "railgun_s", x = 2, y = 3, rotation = "east"},
+    ]
+
+  [[arena.team]]
+  name = "Default"
+    [[arena.team.ship]]
+    schematic = "cruiser"
+    count = 6
+    modules = [
+      {type = "railgun_m", x = 0, y = 1, rotation = "east"},
+      {type = "railgun_m", x = 2, y = 1, rotation = "east"},
+      {type = "armor_plates", x = 1, y = 0, rotation = "east"},
+      {type = "maneuvering_thrusters", x = 1, y = 3, rotation = "east"},
+    ]
+
 [[arena]]
 name = "Repair escort vs raw numbers (444 vs 444)"
 height_tiles = 10