feat(default-mode): auto-activate ultrawork and ralph loop without commands

Add new `default_mode` config section with two boolean fields:
- `ultrawork`: Auto-inject ultrawork mode prompt on main session start
  without requiring the "ultrawork"/"ulw" keyword. Wired through the
  keyword-detector hook — injects once per session, respects existing
  guards (non-OMO agents, planner agents, subagent sessions).
- `ralph_loop`: Auto-start ralph loop on first main session message
  without requiring /ralph-loop or /ulw-loop commands. When ultrawork
  is also enabled, the loop starts in ultrawork mode.

Usage:
  ```jsonc
  {
    "default_mode": {
      "ultrawork": true,    // Always get ultrawork prompt on start
      "ralph_loop": true    // Auto-start ralph loop
    }
  }
  ```

Files: 7 modified/added, ~65 LOC added.

src/plugin/chat-message.ts

@@ -304,6 +304,25 @@ export function createChatMessageHandler(args: {
       } else if (isCancelRalphTemplate || rawLoopCommand?.command === "cancel-ralph") {
         hooks.ralphLoop.cancelLoop(input.sessionID)
       }
+
+      if (
+        !isRalphLoopTemplate
+        && !isUlwLoopTemplate
+        && !isCancelRalphTemplate
+        && !rawLoopCommand
+        && isFirstMessage
+        && pluginConfig.default_mode?.ralph_loop
+      ) {
+        const loopPrompt = promptText
+        const ultrawork = pluginConfig.default_mode?.ultrawork ?? false
+        hooks.ralphLoop.startLoop(input.sessionID, loopPrompt, {
+          ultrawork,
+        })
+        log("[chat-message] Default ralph loop auto-started", {
+          sessionID: input.sessionID,
+          ultrawork,
+        })
+      }
     }
 
     await applyUltraworkModelOverrideOnMessage(

src/plugin/hooks/create-transform-hooks.ts

@@ -61,6 +61,7 @@ export function createTransformHooks(args: {
             contextCollector,
             ralphLoop ?? undefined,
             pluginConfig.keyword_detector,
+            pluginConfig.default_mode,
           ),
         { enabled: safeHookEnabled },
       )