refactor: compact copilot sessions through sdk state

Route Copilot compaction through SDK-backed state, remove marker sidecars, preserve auth/session binding behavior in SQLite-backed plugin state, and route Copilot CLI budget compaction through native harness compaction.

src/agents/command/cli-compaction.test.ts

@@ -280,6 +280,8 @@ describe("runCliTurnCompactionLifecycle", () => {
       totalTokens: 950,
       totalTokensFresh: true,
       agentHarnessId: "codex",
+      authProfileOverride: "github-copilot:work",
+      authProfileOverrideSource: "auto",
     };
     const sessionStore: Record<string, SessionEntry> = { [sessionKey]: sessionEntry };
     await fs.writeFile(storePath, JSON.stringify(sessionStore, null, 2), "utf-8");
@@ -368,9 +370,13 @@ describe("runCliTurnCompactionLifecycle", () => {
       currentTokenCount: 950,
       contextEngine,
       agentHarnessId: "codex",
+      authProfileId: "github-copilot:work",
       trigger: "budget",
       force: true,
     });
+    expect(compactAgentHarnessSessionCalls[0]?.[0].contextEngineRuntimeContext).toMatchObject({
+      authProfileId: "github-copilot:work",
+    });
     expect(compactCalls).toHaveLength(0);
     expect(recordCliCompactionInStore).toHaveBeenCalledTimes(1);
     expect(recordCliCompactionInStore).toHaveBeenCalledWith(
@@ -383,11 +389,11 @@ describe("runCliTurnCompactionLifecycle", () => {
     expect(updatedEntry?.compactionCount).toBe(1);
   });
 
-  it("treats below-target Codex native CLI compaction as a no-op", async () => {
-    const sessionKey = "agent:main:codex-under-target";
-    const sessionId = "session-codex-under-target";
-    const sessionFile = path.join(tmpDir, "session-codex-under-target.jsonl");
-    const storePath = path.join(tmpDir, "sessions-codex-under-target.json");
+  it("treats below-target Copilot native CLI compaction as a no-op", async () => {
+    const sessionKey = "agent:main:copilot-under-target";
+    const sessionId = "session-copilot-under-target";
+    const sessionFile = path.join(tmpDir, "session-copilot-under-target.jsonl");
+    const storePath = path.join(tmpDir, "sessions-copilot-under-target.json");
     await writeSessionFile({ sessionFile, sessionId });
 
     const sessionEntry: SessionEntry = {
@@ -397,7 +403,7 @@ describe("runCliTurnCompactionLifecycle", () => {
       contextTokens: 1_000,
       totalTokens: 950,
       totalTokensFresh: true,
-      agentHarnessId: "codex",
+      agentHarnessId: "copilot",
     };
     const sessionStore: Record<string, SessionEntry> = { [sessionKey]: sessionEntry };
     await fs.writeFile(storePath, JSON.stringify(sessionStore, null, 2), "utf-8");
@@ -441,7 +447,7 @@ describe("runCliTurnCompactionLifecycle", () => {
       sessionAgentId: "main",
       workspaceDir: tmpDir,
       agentDir: tmpDir,
-      provider: "codex",
+      provider: "github-copilot",
       model: "gpt-5.5",
     });
 
@@ -934,6 +940,8 @@ describe("runCliTurnCompactionLifecycle", () => {
       totalTokens: 950,
       totalTokensFresh: true,
       agentHarnessId: "codex",
+      authProfileOverride: "github-copilot:work",
+      authProfileOverrideSource: "auto",
     };
     const sessionStore: Record<string, SessionEntry> = { [sessionKey]: sessionEntry };
     await fs.writeFile(storePath, JSON.stringify(sessionStore, null, 2), "utf-8");
@@ -992,6 +1000,9 @@ describe("runCliTurnCompactionLifecycle", () => {
 
     expect(compactAgentHarnessSession).toHaveBeenCalledTimes(1);
     expect(compactCalls).toHaveLength(1);
+    expect(compactCalls[0]?.runtimeContext).toMatchObject({
+      authProfileId: "github-copilot:work",
+    });
     expect(maintenance).toHaveBeenCalledTimes(1);
     expect(recordCliCompactionInStore).toHaveBeenCalledWith(
       expect.objectContaining({

src/agents/command/cli-compaction.ts

@@ -87,6 +87,7 @@ type CliCompactionRuntimeContextParams = {
   sessionKey: string;
   messageChannel?: string;
   agentAccountId?: string;
+  authProfileId?: string;
   workspaceDir: string;
   cwd?: string;
   agentDir: string;
@@ -174,8 +175,8 @@ function isNativeHarnessCompactionSession(
   const providerId = provider.trim().toLowerCase();
   return (
     harnessId === providerId ||
-    (harnessId === "codex" &&
-      (providerId === "codex" || providerId === "openai" || providerId === "openai"))
+    (harnessId === "copilot" && providerId === "github-copilot") ||
+    (harnessId === "codex" && (providerId === "codex" || providerId === "openai"))
   );
 }
 
@@ -211,7 +212,7 @@ function buildCliCompactionRuntimeContext(params: CliCompactionRuntimeContextPar
       messageChannel: params.messageChannel,
       messageProvider: params.messageChannel,
       agentAccountId: params.agentAccountId,
-      authProfileId: undefined,
+      authProfileId: params.authProfileId,
       workspaceDir: params.workspaceDir,
       cwd: params.cwd,
       agentDir: params.agentDir,
@@ -246,6 +247,7 @@ async function compactCliTranscript(params: {
   skillsSnapshot?: SkillSnapshot;
   messageChannel?: string;
   agentAccountId?: string;
+  authProfileId?: string;
   senderIsOwner?: boolean;
   thinkLevel?: Parameters<typeof buildEmbeddedCompactionRuntimeContext>[0]["thinkLevel"];
   extraSystemPrompt?: string;
@@ -255,6 +257,7 @@ async function compactCliTranscript(params: {
     sessionKey: params.sessionKey,
     messageChannel: params.messageChannel,
     agentAccountId: params.agentAccountId,
+    authProfileId: params.authProfileId,
     workspaceDir: params.workspaceDir,
     cwd: params.cwd,
     agentDir: params.agentDir,
@@ -360,6 +363,7 @@ async function compactNativeHarnessCliTranscript(params: {
   try {
     const sessionAgentId = readAgentIdFromSessionKey(params.sessionKey);
     const nativeHarnessId = params.sessionEntry.agentHarnessId?.trim();
+    const authProfileId = params.sessionEntry.authProfileOverride?.trim() || undefined;
     await cliCompactionDeps.ensureSelectedAgentHarnessPlugin({
       provider: params.provider,
       modelId: params.model,
@@ -382,6 +386,7 @@ async function compactNativeHarnessCliTranscript(params: {
           skillsSnapshot: params.skillsSnapshot,
           provider: params.provider,
           model: params.model,
+          authProfileId,
           contextTokenBudget: params.contextTokenBudget,
           currentTokenCount: params.currentTokenCount,
           trigger: "budget",
@@ -399,6 +404,7 @@ async function compactNativeHarnessCliTranscript(params: {
                   sessionKey: params.sessionKey,
                   messageChannel: params.messageChannel,
                   agentAccountId: params.agentAccountId,
+                  authProfileId,
                   workspaceDir: params.workspaceDir,
                   cwd: params.cwd,
                   agentDir: params.agentDir,
@@ -526,6 +532,7 @@ export async function runCliTurnCompactionLifecycle(params: {
   let nativeFallbackNeedsBindingClear = false;
   let resolvedContextEngine: ContextEngine | undefined;
   let autoCompactionGuardApplied = false;
+  const authProfileId = params.sessionEntry?.authProfileOverride?.trim() || undefined;
   const applyAutoCompactionGuard = async (contextEngine: ContextEngine): Promise<void> => {
     if (autoCompactionGuardApplied) {
       return;
@@ -606,6 +613,7 @@ export async function runCliTurnCompactionLifecycle(params: {
       skillsSnapshot: params.skillsSnapshot,
       messageChannel: params.messageChannel,
       agentAccountId: params.agentAccountId,
+      authProfileId,
       senderIsOwner: params.senderIsOwner,
       thinkLevel: params.thinkLevel,
       extraSystemPrompt: params.extraSystemPrompt,