refactor(bild): simplify terminal output - use --loud flag

- Remove BILD_OUTPUT_MODE environment variable - Simplify to 2
modes: MultiLine (≥80 cols) and SingleLine (<80) - Use existing
--loud flag to disable concurrent UI entirely - When --loud: show
all compiler output line-by-line (for debugging) - When not --loud:
adaptive concurrent UI based on terminal width

This is simpler and uses the existing --loud flag instead of adding
new configuration. The --loud flag was already meant for debugging,
so it makes sense to use it to show all output.

Note: Omni/Bild.nix updated to include new Omni/Log/Terminal.hs module.

Blocked by: stdin bug (see _/llm/STDIN_BUG.md) - cannot test build yet.

1 files changed, 6 insertions, 16 deletions

diff --git a/Omni/Log/Terminal.hs b/Omni/Log/Terminal.hs
index 1230eb3..6d5d70c 100644
--- a/Omni/Log/Terminal.hs
+++ b/Omni/Log/Terminal.hs
@@ -16,9 +16,8 @@ import qualified System.Console.ANSI as ANSI
 import qualified System.Environment as Env
 
 data OutputMode
-  = RichMultiLine -- Wide terminals (≥80 cols)
-  | SingleLine -- Narrow terminals (40-79 cols)
-  | SimpleFallback -- Very narrow (<40) or dumb terminals
+  = MultiLine -- Wide terminals (≥80 cols) - reserved lines per namespace
+  | SingleLine -- Narrow terminals (<80 cols) - rotating single line
   deriving (Eq, Show)
 
 data TerminalInfo = TerminalInfo
@@ -33,7 +32,6 @@ detectTerminal :: IO TerminalInfo
 detectTerminal = do
   term <- Env.lookupEnv "TERM"
   area <- Env.lookupEnv "AREA"
-  modeOverride <- Env.lookupEnv "BILD_OUTPUT_MODE"
 
   -- Check if we support ANSI
   let supportsANSI = case (term, area) of
@@ -48,19 +46,11 @@ detectTerminal = do
         Just (h, w) -> (w, h)
         Nothing -> (80, 24) -- sensible default
 
-  -- Determine mode
-  let autoMode
-        | not supportsANSI = SimpleFallback
-        | width < 40 = SimpleFallback
+  -- Determine mode based on terminal width
+  let mode
+        | not supportsANSI = SingleLine -- Fallback to single line for dumb terminals
         | width < 80 = SingleLine
-        | otherwise = RichMultiLine
-
-  -- Allow manual override
-  let mode = case modeOverride of
-        Just "simple" -> SimpleFallback
-        Just "single" -> SingleLine
-        Just "rich" -> RichMultiLine
-        _ -> autoMode
+        | otherwise = MultiLine
 
   pure
     TerminalInfo