feat(context): purify leading SYSTEM, route context layers as USER turns (#290)

Move intent, repo map, docs catalog, decision journal and relevant-files
context entries to EntryRole.USER so they no longer fold into the single
leading SYSTEM block — that block stays pure policy/schema. Omit L3 repo-map
retrieval on repair retries (the transcript already carries the evidence).
Add "initialIntent" to REQUIRED_SOURCE_TYPES.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

testing/integration/src/test/kotlin/ToolCallGateTest.kt

@@ -110,7 +110,9 @@ class ToolCallGateTest {
 
     /** A tool that declares an output compressor (strips blank lines) — the Tier-A seam under test. */
     private inner class FakeCompressingTool(override val tier: Tier = Tier.T1) : Tool {
-        override val name = "file_write"
+        // Non-write tool: #289 elides successful write receipts before FORMAT_COMPRESS, so this
+        // must be a generic tool to actually exercise the outputCompressor (blank-line stripping).
+        override val name = "shell_run"
         override val description = "fake compressing tool"
         override val parametersSchema: JsonObject = buildJsonObject {}
         override val requiredCapabilities: Set<ToolCapability> = setOf(ToolCapability.FILE_WRITE)
@@ -374,7 +376,7 @@ class ToolCallGateTest {
         val (orchestrator, _, provider) = buildOrchestrator(executor, FakeCompressingTool(), assessorRule = null)
         val config = OrchestrationConfig(retryPolicy = RetryPolicy(maxAttempts = 1, backoffMs = 0))
 
-        orchestrator.run(SessionId("compress"), singleStageGraph(), config)
+        orchestrator.run(SessionId("compress"), singleStageGraph(setOf("shell_run")), config)
 
         // The second inference carries round-1's tool result in its context pack — compressed
         // (blank lines stripped), not raw, under the uniform `[tool exit=N]` frame the model sees.
@@ -382,7 +384,7 @@ class ToolCallGateTest {
         // only shapes the derived context entry.
         val secondPack = provider.requests[1].contextPack
         val toolEntry = secondPack.layers.values.flatten().first { it.sourceType == "toolResult" }
-        assertEquals("[file_write exit=0]\nline1\nline2\nline3", toolEntry.content)
+        assertEquals("[shell_run exit=0]\nline1\nline2\nline3", toolEntry.content)
     }
 
     @Test