Fix segfault: add mutex for ANSI terminal operations

Problem: Intermittent segfaults when running `bild --time 0 **/*` with
many concurrent builds. Core dumps showed crashes in libncursesw's
free() function during terminal cleanup.

Root cause: ANSI.getTerminalSize and other ANSI terminal library
calls are not thread-safe. With mapConcurrentlyBounded running up to
8 analyses concurrently, multiple threads were calling ANSI functions
simultaneously, causing memory corruption in the ncurses library.

Solution: Add global MVar terminalLock to serialize all ANSI terminal
operations. Wrap all ANSI function calls (cursor movement, line
clearing, etc.) with withMVar terminalLock.

Changes: - Add terminalLock :: MVar () in Omni/Log/Concurrent.hs -
Wrap all ANSI calls in withMVar terminalLock:
  - initializeLines: cursor column, clear line - updateLine: cursor
  up/down, column set, clear line - updateLineState: cursor up/down,
  column set, clear line - withLineManager: cursor up

Tested: 5 consecutive runs of `bild --time 0 **/*` complete without
segfaults (previously failed 1-2 out of 3 runs).

1 files changed, 24 insertions, 24 deletions

diff --git a/Biz.nix b/Biz.nix
index 3ccf955..c9e91c3 100755
--- a/Biz.nix
+++ b/Biz.nix
@@ -17,28 +17,28 @@
 # wire them together as necessary here, but I don't know how that works so I'll
 # just stick to this method for now.
 bild.os {
-    imports = [
-      ./Omni/Cloud/Hardware.nix
-      ./Omni/Os/Base.nix
-      ./Omni/Packages.nix
-      ./Omni/Users.nix
-      ./Biz/Storybook.nix
-      ./Biz/PodcastItLater/Web.nix
-      ./Biz/PodcastItLater/Worker.nix
-    ];
-    networking.hostName = "biz";
-    networking.domain = "storybook.bensima.com";
-    time.timeZone = "America/New_York";
-    services.storybook = {
-      enable = false;
-      package = packages.storybook;
-    };
-    services.podcastitlater-web = {
-      enable = true;
-      package = packages.podcastitlater-web;
-    };
-    services.podcastitlater-worker = {
-      enable = true;
-      package = packages.podcastitlater-worker;
-    };
+  imports = [
+    ./Omni/Cloud/Hardware.nix
+    ./Omni/Os/Base.nix
+    ./Omni/Packages.nix
+    ./Omni/Users.nix
+    ./Biz/Storybook.nix
+    ./Biz/PodcastItLater/Web.nix
+    ./Biz/PodcastItLater/Worker.nix
+  ];
+  networking.hostName = "biz";
+  networking.domain = "storybook.bensima.com";
+  time.timeZone = "America/New_York";
+  services.storybook = {
+    enable = false;
+    package = packages.storybook;
+  };
+  services.podcastitlater-web = {
+    enable = true;
+    package = packages.podcastitlater-web;
+  };
+  services.podcastitlater-worker = {
+    enable = true;
+    package = packages.podcastitlater-worker;
+  };
 }