fix(kernel,server,workflow): per-stage retry budget, sane freestyle budget, tail /events

Three defects surfaced by a live headless freestyle_planning run (all made a
long execution workflow fail or stall in ways invisible to a REST operator):

1. retryCount was session-global (DefaultOrchestrationReducer): TransitionExecuted
   updated currentStageId but never reset retryCount, while shouldRetry gates on
   it per-stage. An early stage that burned its 3 retries starved every later
   stage of its own — the next stage's first *retryable* failure went terminal.
   Reset retryCount on stage entry; back-edge loops stay bounded by the separate
   refinementIterations counter. Regression test added.

2. Freestyle stages ran at StageConfig's 4096-token default (ExecutionPlanCompiler
   never set a budget) vs 16384-32768 for static role_pipeline stages. A tool-heavy
   stage truncated its context every round, evicting the file_read results it just
   gathered, so it re-read forever and never accumulated enough to write. Set 16384.

3. GET /events returned the OLDEST `limit` events (readFrom(0) then take): for a
   session past `limit` events the tail — including a pending ApprovalRequested —
   was invisible to a headless/REST poller, the exact caller POST /approve serves.
   Default now tails; explicit fromSeq still paginates forward.

testing/projections/src/test/kotlin/OrchestrationReducerTest.kt

@@ -1,6 +1,7 @@
 import com.correx.core.events.events.OrchestrationPausedEvent
 import com.correx.core.events.events.OrchestrationResumedEvent
 import com.correx.core.events.events.RetryAttemptedEvent
+import com.correx.core.events.events.TransitionExecutedEvent
 import com.correx.core.events.events.WorkflowCompletedEvent
 import com.correx.core.events.events.WorkflowFailedEvent
 import com.correx.core.events.events.WorkflowStartedEvent
@@ -8,6 +9,7 @@ import com.correx.core.events.orchestration.OrchestrationState
 import com.correx.core.events.orchestration.OrchestrationStatus
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
+import com.correx.core.events.types.TransitionId
 import com.correx.core.kernel.orchestration.DefaultOrchestrationReducer
 import com.correx.testing.fixtures.EventFixtures.stored
 import org.junit.jupiter.api.Assertions.assertEquals
@@ -133,6 +135,23 @@ class OrchestrationReducerTest {
         assertNull(retrying1.failureReason)
     }
 
+    @Test
+    fun `TransitionExecutedEvent resets retryCount so each stage gets its own retry budget`() {
+        val exhausted = reducer.reduce(
+            state,
+            stored(payload = RetryAttemptedEvent(sessionId, stageId, 3, 3, "boom")),
+        )
+        assertEquals(3, exhausted.retryCount)
+
+        val nextStage = StageId("stage-2")
+        val advanced = reducer.reduce(
+            exhausted,
+            stored(payload = TransitionExecutedEvent(sessionId, stageId, nextStage, TransitionId("t1"))),
+        )
+        assertEquals(nextStage, advanced.currentStageId)
+        assertEquals(0, advanced.retryCount)
+    }
+
 
     @Test
     fun `unrelated event does nothing`() {