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/history.md

@@ -94,3 +94,34 @@ range 200).
   — ~1 expansion per cycle mid-game, 2–3 cycles apart late.
 - **First full balancing round complete.** Next: full-game playtests
   against the run-shape targets.
+
+## 2026-07-06 — playtest 1 (first two pushes)
+
+First real run: two enemy stations destroyed in ~40 min game time
+(~80 min real time with heavy build-pausing) — roughly on pace for the
+≤2 h game-time target, so pacing untouched.
+
+- **Meta finding: cruisers filled with 12× railgun_s dominate.** Predicted
+  by the numbers in hindsight: the concentration tax makes railgun_s the
+  best DPS/threat (0.62 vs m 0.48, l 0.41), range is the big guns' only
+  mechanical edge (armor is added HP, not damage reduction — no anti-swarm
+  mechanic), repair sustain covers the closing distance, and stations
+  outranged every ship gun (120 vs railgun_l's 100), so even capitals had
+  to tank-and-brawl. The cruiser compounds it: first hull with a large
+  1×1 canvas (12 cells) and a nearly quartz-free chain.
+- **Repair tool confirmed overpowered** (second signal after the
+  persistent +24% arena escort margin): the arena only prices in-fight
+  sustain; real runs add free full top-offs in every 15–45 s wave gap
+  across the whole swarm. The 0.7 HP/s-per-threat prior is wrong for
+  wave defence.
+- **Changes:** repair_tool 9→4 HP/s; railgun_l range 100→130 (now
+  outranges stations — buys the siege role the capital ladder promises);
+  railgun_m 14→16 dmg and range 70→80 (tax softened: m sits at 0.55
+  DPS/threat, between s and l). Module threats unchanged (costs
+  untouched), so no ladder recalculation needed.
+- New tracked arena added: railgun_s-spam cruisers (8× 178) vs default
+  cruisers (6× 233.5) — the spam side should win a brawl somewhat, but a
+  blowout means the small-gun premium needs retuning.
+- **Open:** re-run the arena suite to check the range/damage changes
+  against the round 1–5 results; next playtest should verify big guns now
+  feel worth climbing to and repair is merely good.