feat(ralph-loop): add strategy option for fresh context per iteration

Closes #1901

Add 'default_strategy' config option (default: 'continue') to control whether ralph-loop creates a new session per iteration ('reset') or keeps the same session ('continue'). The 'reset' strategy keeps the model in the smart zone by starting with fresh context for each iteration.

Supports --strategy flag for per-command override.

src/hooks/ralph-loop/storage.ts

@@ -49,6 +49,7 @@ export function readState(directory: string, customPath?: string): RalphLoopStat
       prompt: body.trim(),
       session_id: data.session_id ? stripQuotes(data.session_id) : undefined,
       ultrawork: data.ultrawork === true || data.ultrawork === "true" ? true : undefined,
+      strategy: data.strategy === "reset" || data.strategy === "continue" ? data.strategy : undefined,
     }
   } catch {
     return null
@@ -70,13 +71,14 @@ export function writeState(
 
     const sessionIdLine = state.session_id ? `session_id: "${state.session_id}"\n` : ""
     const ultraworkLine = state.ultrawork !== undefined ? `ultrawork: ${state.ultrawork}\n` : ""
+    const strategyLine = state.strategy ? `strategy: "${state.strategy}"\n` : ""
     const content = `---
 active: ${state.active}
 iteration: ${state.iteration}
 max_iterations: ${state.max_iterations}
 completion_promise: "${state.completion_promise}"
 started_at: "${state.started_at}"
-${sessionIdLine}${ultraworkLine}---
+${sessionIdLine}${ultraworkLine}${strategyLine}---
 ${state.prompt}
 `