fix(notepad-guard,start-work): wire dispatch and match .omo paths

notepad-write-guard:
- The hook was created by create-tool-guard-hooks but tool-execute-before
  never invoked it, so the guard was inert.
- It also only matched .sisyphus/notepads, missing the current
  .omo/notepads layout introduced by the workspace migration.
- Add the dispatch call alongside writeExistingFileGuard, and extend
  NOTEPAD_ROOTS to cover both paths via normalize() + sep. New
  integration test pins the wire and the .omo block; the existing unit
  test now asserts both paths.

start-work session-plan-affinity:
- PLAN_PATH_PATTERN only matched .sisyphus/plans, so sessions referring
  to plans under .omo/plans returned null and start-work missed the
  current session's own plan.
- Extend the regex to .(sisyphus|omo)/plans and add findPrometheusPlans
  in packages/boulder-state to scan both directories during the
  transition. New regression test pins .omo/plans matching; legacy
  .sisyphus/plans coverage preserved.

packages/boulder-state/src/storage/plan-progress.ts

@@ -11,19 +11,23 @@ const UNCHECKED_CHECKBOX_PATTERN = /^(\s*)[-*]\s*\[\s*\]\s*(.+)$/
 const CHECKED_CHECKBOX_PATTERN = /^(\s*)[-*]\s*\[[xX]\]\s*(.+)$/
 const TODO_TASK_PATTERN = /^\d+\.\s+/
 const FINAL_WAVE_TASK_PATTERN = /^F\d+\.\s+/i
+const LEGACY_PROMETHEUS_PLANS_DIR = ".sisyphus/plans"
+const PROMETHEUS_PLAN_DIRS = [PROMETHEUS_PLANS_DIR, LEGACY_PROMETHEUS_PLANS_DIR] as const
 
 type ProgressSection = "todo" | "final-wave" | "other"
 
 export function findPrometheusPlans(directory: string): string[] {
-  const plansDir = join(directory, PROMETHEUS_PLANS_DIR)
-  if (!existsSync(plansDir)) {
-    return []
-  }
-
   try {
-    return readdirSync(plansDir)
-      .filter((file) => file.endsWith(".md"))
-      .map((file) => join(plansDir, file))
+    return PROMETHEUS_PLAN_DIRS.flatMap((planDir) => {
+      const plansDir = join(directory, planDir)
+      if (!existsSync(plansDir)) {
+        return []
+      }
+
+      return readdirSync(plansDir)
+        .filter((file) => file.endsWith(".md"))
+        .map((file) => join(plansDir, file))
+    })
       .sort((left, right) => statSync(right).mtimeMs - statSync(left).mtimeMs)
   } catch {
     return []