docs(site): edit rules for clarity + cross-links; migrate off rules.txt

Editorial pass over site/ru/rules.md (on top of the verbatim port):
- moved the lore intro to the RU home page, rewritten in a modern voice;
- fixed typos, replaced the TODO/WTF cargo-tech note and the abandoned
  (---ссылка---) marker with the verified mechanic and a real cross-link,
  dropped the report TODO row;
- wove organic intra-page cross-links (#combat, #movement, #victory, ...);
- documented engine nuances verified against the code: ore auto-farming
  and the capital / "запасы промышленности" store (industry capped at
  population); cargo lost with ships destroyed in battle; and that a
  losing race's colonists at a neutral planet are NOT lost — they stay
  aboard (this corrects the audit note, verified in route.go).

Migration: delete game/rules.txt (its content now lives, authoritative,
in site/ru/rules.md) and repoint every reference to it (ui/frontend code
comments + tests, ui/docs, tools, ui/PLAN.md links). Record the
RU-authoritative rule in site/README.md and CLAUDE.md. The English
site/rules.md mirror follows in a separate stage.

ui/docs/calculator-ux.md

@@ -136,7 +136,7 @@ new one); Create is disabled while the name is invalid or duplicate
 (reusing `lib/util/ship-class-validation.ts`). Create reuses the existing
 `createShipClass` order-draft flow, so the optimistic overlay reflects
 the change immediately. Ship classes are immutable after creation (per
-`game/rules.txt`), so there is no edit — only Create-new. Delete-class
+`site/ru/rules.md`), so there is no edit — only Create-new. Delete-class
 lives in the ship-classes table (`lib/active-view/table-ship-classes.svelte`),
 not the calculator.
 

ui/docs/cargo-routes-ux.md

@@ -5,8 +5,7 @@ subsection (a single-row dropdown + contextual actions after
 F8-05), the map-driven destination pick, and the optimistic
 overlay that keeps the inspector and the map in lock-step with
 the local order draft. The engine semantics are quoted from
-[`game/rules.txt`](../../game/rules.txt) section "Грузовые маршруты"
-(lines 808–843); this file is the source of truth for how the UI
+[`site/ru/rules.md`](../../site/ru/rules.md#routes) section "Грузовые маршруты"; this file is the source of truth for how the UI
 surfaces those rules.
 
 ## Engine semantics in one paragraph

ui/docs/science-designer-ux.md

@@ -29,8 +29,8 @@ sequence.
 
 The designer presents the four proportions as percentages
 (`step="0.1"`, range `[0, 100]`) so the player can type and reason
-about whole-number splits — closer to how `game/rules.txt` describes
-sciences (`game/rules.txt:345-362`: "10 parts Drive, 5 parts
+about whole-number splits — closer to how `site/ru/rules.md` describes
+sciences (`site/ru/rules.md` #sciences: "10 parts Drive, 5 parts
 Weapons, 30 parts Shields, 0 parts Cargo, …"). The wire shape is
 still fractions; conversion happens inside `validateScience` only on
 Save (`value / 100` for each of the four).