refactor(simulation): move content/ under server/ (#669)

Content files (RON templates, YAML campaigns, gauntlet data) are consumed
exclusively by the server. Colocate them at server/content/ and update all
path references in Rust source, tooling scripts, and schema files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/content/global/factions/concord-assembly.yaml

@@ -0,0 +1 @@
+# Faction: concord-assembly

server/content/global/factions/guardians-of-autonomy.yaml

@@ -0,0 +1 @@
+# Faction: guardians-of-autonomy

server/content/global/factions/syndics.yaml

@@ -0,0 +1 @@
+# Faction: syndics

server/content/global/factions/the-ring.yaml

@@ -0,0 +1 @@
+# Faction: the-ring

server/content/global/factions/the-unbound.yaml

@@ -0,0 +1 @@
+# Faction: the-unbound

server/content/global/factions/veil-institute.yaml

@@ -0,0 +1 @@
+# Faction: veil-institute