Initial commit: Brass & Sigil monorepo

Self-hosted Minecraft modpack distribution + administration system.

- launcher/  Avalonia 12 desktop client; single-file win-x64 publish.
             Microsoft auth via XboxAuthNet, manifest+SHA-1 mod sync,
             portable install path, sidecar settings.
- server/    brass-sigil-server daemon (.NET 8, linux-x64). Wraps the
             MC subprocess, embedded Kestrel admin panel with cookie
             auth + rate limiting, RCON bridge, scheduled backups,
             BlueMap CLI integration with player markers + skin proxy,
             friend-side whitelist request flow, world wipe with seed
             selection (keep current / random / custom).
- pack/      pack.lock.json (Modrinth + manual CurseForge entries),
             data-only tweak source under tweaks/, build outputs in
             overrides/ (gitignored).
- scripts/   Build-Pack / Build-Tweaks / Update-Pack / Check-Updates
             plus Deploy-Brass.ps1 unified one-shot deploy with
             version-bump pre-flight and daemon-state detection.

pack/tweaks/brassandsigil-tweaks/META-INF/neoforge.mods.toml

@@ -0,0 +1,42 @@
+modLoader = "lowcodefml"
+loaderVersion = "[1,)"
+license = "All Rights Reserved"
+issueTrackerURL = "https://sijbers.uk/pack/"
+
+[[mods]]
+modId = "brassandsigil_tweaks"
+version = "1.0.0"
+displayName = "Brass & Sigil Tweaks"
+description = '''
+Server-and-client worldgen and balance tweaks for the Brass & Sigil modpack.
+Ships custom configured features, placed features, and Lithostitched worldgen
+modifiers that retune third-party content for this pack.
+'''
+
+[[dependencies.brassandsigil_tweaks]]
+    modId = "neoforge"
+    type = "required"
+    versionRange = "[21.1,)"
+    ordering = "NONE"
+    side = "BOTH"
+
+[[dependencies.brassandsigil_tweaks]]
+    modId = "minecraft"
+    type = "required"
+    versionRange = "[1.21.1,1.22)"
+    ordering = "NONE"
+    side = "BOTH"
+
+[[dependencies.brassandsigil_tweaks]]
+    modId = "lithostitched"
+    type = "required"
+    versionRange = "[1.7,)"
+    ordering = "NONE"
+    side = "BOTH"
+
+[[dependencies.brassandsigil_tweaks]]
+    modId = "terralith"
+    type = "required"
+    versionRange = "[2.5,)"
+    ordering = "AFTER"
+    side = "BOTH"