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/frontend/src/api/game-state.ts

@@ -268,7 +268,7 @@ export interface ReportLocalFleet {
  * table uses.
  *
  * `relation` reflects the local player's stance TOWARD this race,
- * not the other way around (`rules.txt` line 1162). Per the engine
+ * not the other way around (`site/ru/rules.md` #report). Per the engine
  * (`controller/race.go.UpdateRelation`) the relation is stored
  * unilaterally — race A can be at war with race B while race B is
  * at peace with race A.
@@ -508,7 +508,7 @@ export interface GameReport {
 	/**
 	 * myVotes is the local player's total vote weight in the current
 	 * report, read from `Report.votes` (the engine assigns one vote
-	 * per 1000 population, see `rules.txt:1060`). Zero when the
+	 * per 1000 population, see `site/ru/rules.md` #victory). Zero when the
 	 * report has not been produced yet.
 	 */
 	myVotes: number;

ui/frontend/src/lib/active-view/table-races.svelte

@@ -8,7 +8,7 @@ immediately and the auto-sync pipeline drives the server in the
 background.
 
 The alliance graph and the 2/3 victory check are NOT computed
-here: `rules.txt` keeps each race's outgoing vote target private
+here: `site/ru/rules.md` keeps each race's outgoing vote target private
 (only the votes a race RECEIVED in the last tally and the local
 player's own pick are observable), and the acceptance criterion
 "vote counts match server state byte-for-byte" rules out

ui/frontend/src/lib/util/science-validation.ts

@@ -10,7 +10,7 @@
 // `OrderCommand` payload always carries the canonical `[0, 1]`
 // summing to `1.0` shape the FBS encoder ships on the wire.
 //
-// Engine rules (from `pkg/calc/validator.go` and `game/rules.txt`):
+// Engine rules (from `pkg/calc/validator.go` and `site/ru/rules.md`):
 //
 //   - drive, weapons, shields, cargo: float in `[0, 1]`;
 //   - the four values sum to `1.0` (the engine accepts a small

ui/frontend/src/lib/util/ship-class-validation.ts

@@ -6,7 +6,7 @@
 // to gate auto-sync, so the local invariants match the engine's
 // (`game/internal/controller/ship_class.go.ShipClassCreate`).
 //
-// Engine rules (from `pkg/calc/validator.go` and `game/rules.txt`):
+// Engine rules (from `pkg/calc/validator.go` and `site/ru/rules.md`):
 //
 //   - drive, weapons, shields, cargo: float, equal to 0 or >= 1;
 //   - armament: integer, >= 0;

ui/frontend/src/sync/order-draft.svelte.ts

@@ -330,7 +330,7 @@ export class OrderDraftStore {
 	 *     tracks a single war/peace stance per opponent, so a newer
 	 *     entry supersedes any prior `setDiplomaticStance` for the
 	 *     same other race.
-	 *   - `setVoteRecipient` collapses singleton: per `rules.txt`
+	 *   - `setVoteRecipient` collapses singleton: per `site/ru/rules.md`
 	 *     each race controls a single vote slot, so a newer entry
 	 *     supersedes any prior `setVoteRecipient` regardless of the
 	 *     acceptor.

ui/frontend/src/sync/order-types.ts

@@ -463,7 +463,7 @@ export interface SetDiplomaticStanceCommand {
  * to a race. Mirrors the engine `CommandRaceVote`
  * (`pkg/schema/fbs/order.fbs`,
  * `game/internal/controller/command.go.RaceVote`). The engine
- * tallies votes at turn cutoff (`rules.txt` "Процесс голосования");
+ * tallies votes at turn cutoff (`site/ru/rules.md` "Процесс голосования");
  * between turns the player can change their pick freely. The
  * acceptor may be the local race itself — the engine treats
  * self-vote as the neutral default and re-applies it whenever a

ui/frontend/tests/science-validation.test.ts

@@ -112,7 +112,7 @@ describe("validateScience", () => {
 		expect(result.reason).toBe("sum_not_hundred");
 	});
 
-	test("accepts the canonical First Step fixture from rules.txt", () => {
+	test("accepts the canonical First Step fixture from site/ru/rules.md", () => {
 		// 10 Drive + 5 Weapons + 30 Shields + 0 Cargo, normalised:
 		// 10/45 ≈ 22.222… %, 5/45 ≈ 11.111… %, 30/45 ≈ 66.666… %,
 		// 0/45 = 0 %. Snapped to one decimal at input time:

ui/frontend/tests/ship-class-validation.test.ts

@@ -138,7 +138,7 @@ describe("validateShipClass", () => {
 		expect(result.reason).toBe("all_zero");
 	});
 
-	test("accepts the canonical Cruiser fixture from rules.txt", () => {
+	test("accepts the canonical Cruiser fixture from site/ru/rules.md", () => {
 		const result = validateShipClass(
 			draft({
 				name: "Cruiser",