refactor(kernel): rename tabId → conversationId across contracts + consumers (218 tests)

Step 4 of the post-MVP backlog: resolve the last vocab drift. The canonical
term for a thread of turns is `conversationId` (GLOSSARY), but `AgentEvent`
variants and `RunTurnInput` still used the legacy `tabId` from the old frontend
"tab" concept, with session-orchestrator bridging `conversationId → tabId`.

Atomic, type-driven rename across the full 10-file consumer set:
- contracts/events.ts: all 11 AgentEvent variants tabId → conversationId
- contracts/runtime.ts: RunTurnInput.tabId → conversationId
- runtime/{events,run-turn,dispatch}.ts: factory params, ctx field, locals
- session-orchestrator: drop the redundant `tabId: conversationId` bridge line
- transport-http: emit wiring; external /chat field + X-Conversation-Id header
  unchanged (already canonical) — only the emitted NDJSON event field flips
- tests (run-turn, app, logic): inputs + assertions now use conversationId

Pure rename, zero behavior change: typecheck clean, 218 tests pass (unchanged
count), biome clean, `grep tabId packages/` → zero matches. Verified live:
multi-turn curl emits conversationId-keyed NDJSON and threads history correctly.
GLOSSARY drift note removed. Closes the post-MVP backlog (Steps 1–4).

2 files changed, 15 insertions, 15 deletions

diff --git a/packages/kernel/src/contracts/events.ts b/packages/kernel/src/contracts/events.ts
index ce1dae4..74e23fd 100644
--- a/packages/kernel/src/contracts/events.ts
+++ b/packages/kernel/src/contracts/events.ts
@@ -25,24 +25,24 @@ export type AgentEvent =
 	| TurnDoneEvent
 	| TurnSealedEvent;
 
-/** Status change for a tab / session (e.g. idle → running). */
+/** Status change for a conversation (e.g. idle → running). */
 export interface StatusEvent {
 	readonly type: "status";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly status: string;
 }
 
 /** A turn has begun. */
 export interface TurnStartEvent {
 	readonly type: "turn-start";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 }
 
 /** Incremental text content from the model during a turn. */
 export interface TurnTextDeltaEvent {
 	readonly type: "text-delta";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly delta: string;
 }
@@ -50,7 +50,7 @@ export interface TurnTextDeltaEvent {
 /** Incremental reasoning / thinking content during a turn. */
 export interface TurnReasoningDeltaEvent {
 	readonly type: "reasoning-delta";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly delta: string;
 }
@@ -58,7 +58,7 @@ export interface TurnReasoningDeltaEvent {
 /** The model has requested a tool to be run. */
 export interface TurnToolCallEvent {
 	readonly type: "tool-call";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly toolCallId: string;
 	readonly toolName: string;
@@ -68,7 +68,7 @@ export interface TurnToolCallEvent {
 /** A tool has completed execution. */
 export interface TurnToolResultEvent {
 	readonly type: "tool-result";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly toolCallId: string;
 	readonly toolName: string;
@@ -79,7 +79,7 @@ export interface TurnToolResultEvent {
 /** Streaming output from a tool execution (e.g. shell stdout/stderr). */
 export interface TurnToolOutputEvent {
 	readonly type: "tool-output";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly toolCallId: string;
 	readonly data: string;
@@ -89,7 +89,7 @@ export interface TurnToolOutputEvent {
 /** Token usage for the current step or turn. */
 export interface TurnUsageEvent {
 	readonly type: "usage";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly usage: Usage;
 }
@@ -97,7 +97,7 @@ export interface TurnUsageEvent {
 /** An error occurred during the turn. */
 export interface TurnErrorEvent {
 	readonly type: "error";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly message: string;
 	readonly code?: string;
@@ -106,7 +106,7 @@ export interface TurnErrorEvent {
 /** The turn has completed (model finished generating). */
 export interface TurnDoneEvent {
 	readonly type: "done";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 	readonly reason: string;
 }
@@ -117,6 +117,6 @@ export interface TurnDoneEvent {
  */
 export interface TurnSealedEvent {
 	readonly type: "turn-sealed";
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 }
diff --git a/packages/kernel/src/contracts/runtime.ts b/packages/kernel/src/contracts/runtime.ts
index ff994af..68c0444 100644
--- a/packages/kernel/src/contracts/runtime.ts
+++ b/packages/kernel/src/contracts/runtime.ts
@@ -57,10 +57,10 @@ export interface RunTurnInput {
 
 	/**
 	 * Identifiers used to attribute every emitted `AgentEvent`. The kernel does
-	 * not generate these — the session-orchestrator owns turn/tab identity and
-	 * passes them in, so events are traceable to their conversation.
+	 * not generate these — the session-orchestrator owns turn/conversation identity
+	 * and passes them in, so events are traceable to their conversation.
 	 */
-	readonly tabId: string;
+	readonly conversationId: string;
 	readonly turnId: string;
 
 	/**