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

docs/balancing/derived.md

@@ -94,10 +94,14 @@ geometry-validated against the hull grids)
 
 ## Combat stats
 
-(arena-converged, 2026-07; see `history.md` rounds 1–5)
+(arena-converged 2026-07, rounds 1–5; playtest-1 adjustments 2026-07-06 —
+see `history.md`)
 
 **Weapons:** railgun_s 2 dmg × 2.0 Hz (4.0 DPS), range 50 m;
-railgun_m 14 × 1.5 (21), range 70; railgun_l 52 × 0.8 (41.6), range 100.
+railgun_m 16 × 1.5 (24), range 80; railgun_l 52 × 0.8 (41.6), range 130.
+DPS per threat: s 0.62, m 0.55, l 0.41 — the concentration tax softened
+after playtest 1 so the ladder reads "pay some DPS efficiency for reach";
+railgun_l deliberately outranges stations (120 m) to buy the siege role.
 
 **Hull HP** (15/threat prior + empirical trims): drone 60, frigate 300,
 destroyer 550, cruiser 1500, battlecruiser 2400, battleship 6300,
@@ -109,8 +113,9 @@ destroyer 30|35|18|6|3, cruiser 24|25|12|4|2, battlecruiser 20|20|10|3|1.5,
 battleship 15|14|7|2|1, dreadnought/carrier 10|8|4|1|0.5.
 Sensors: 150/200/220/250/260/280/300/350 m.
 
-**Other modules:** armor_plates +1200 HP; repair_tool 9 HP × 1 Hz,
-range 80; salvager range 60, cargo 20, 0.5 collections/s; afterburner
+**Other modules:** armor_plates +1200 HP; repair_tool 4 HP × 1 Hz,
+range 80 (halved after playtest 1 — free between-wave top-offs were never
+priced by the arena escort test); salvager range 60, cargo 20, 0.5 collections/s; afterburner
 ×1.6 speed +60 accel; maneuvering_thrusters ×1.2 speed +10 maneuvering;
 sensor_booster +50 m; weapon_upgrade ×1.2 damage; weapon_primer ×1.2
 rate; weapon_stabilizer ×1.3 range ×0.8 rate.