feat(core): replace instruction checkpoints with value-delta sync

AGENTS.md

@@ -164,5 +164,5 @@ const table = sqliteTable("session", {
 - Keep delivery vocabulary explicit. Prompts steer by default and promote at the next safe step boundary while the current drain requires continuation. An explicit `queue` input remains pending until the Session would otherwise become idle; promote one queued input at that boundary, then reevaluate continuation before promoting another. Promoting any new user input resets the selected agent's step allowance; a batch of steers resets it once.
 - One step is one logical LLM call; its durable record covers only the model-visible span. Do not write "provider turn", and do not use bare "turn" for a single call: "turn" is reserved for the future assistant-turn unit containing all steps from prompt promotion until the session would go idle.
 - Keep EventV2 replay owner claims separate from clustered Session execution ownership.
-- Keep the Instructions algebra and built-ins in `src/instructions`; keep instruction producers with their observed domains, and keep Session History selection plus `InstructionCheckpoint` and `InstructionEntry` persistence Session-owned. `InstructionDiscovery` observes ambient global and upward-project instructions. The runner composes built-ins, discovery, guidance, and entries explicitly in `loadInstructions`; there is no instruction registry.
-- The durable `Instructions.Applied` record is what the model was last told, per instruction source. Reconciliation narrates drift through `session.instructions.updated` and never rewrites the baseline; only completed compaction rebaselines, while Session movement or committed revert resets the `InstructionCheckpoint`. Unavailable sources keep the model's prior belief, blocking only a Session's first instruction baseline.
+- Keep the Instructions algebra and built-ins in `src/instructions`; keep instruction producers with their observed domains, and keep Session History selection plus `InstructionState` and `InstructionEntry` persistence Session-owned. `InstructionDiscovery` observes ambient global and upward-project instructions. The runner composes built-ins, discovery, guidance, and entries explicitly in `loadInstructions`; there is no instruction registry.
+- `session.instructions.updated` stores only changed source keys and content hashes. Blob values live once in `instruction_blob`; `instruction_state` is a rebuildable fold cache, never primary state. Render initial instructions and chronological updates from values during request assembly. Completed compaction moves the instruction epoch; Session movement and committed revert clear it. Unavailable sources retain the last value and block only the initial complete delta.

packages/client/src/promise/generated/client.ts

@@ -701,7 +701,7 @@ export function make(options: ClientOptions) {
                 path: `/api/session/${encodeURIComponent(input.sessionID)}/instructions/entries/${encodeURIComponent(input.key)}`,
                 body: { value: input["value"] },
                 successStatus: 204,
-                declaredStatuses: [404, 400, 401],
+                declaredStatuses: [404, 413, 400, 401],
                 empty: true,
               },
               requestOptions,

packages/client/src/promise/generated/types.ts

@@ -90,6 +90,18 @@ export type UnknownError = {
 export const isUnknownError = (value: unknown): value is UnknownError =>
   typeof value === "object" && value !== null && "_tag" in value && value["_tag"] === "UnknownError"
 
+export type InstructionEntryValueTooLargeError = {
+  readonly _tag: "InstructionEntryValueTooLargeError"
+  readonly actualBytes: number
+  readonly maxBytes: number
+  readonly message: string
+}
+export const isInstructionEntryValueTooLargeError = (value: unknown): value is InstructionEntryValueTooLargeError =>
+  typeof value === "object" &&
+  value !== null &&
+  "_tag" in value &&
+  value["_tag"] === "InstructionEntryValueTooLargeError"
+
 export type ProviderNotFoundError = {
   readonly _tag: "ProviderNotFoundError"
   readonly providerID: string
@@ -1250,9 +1262,9 @@ export type SessionLogOutput =
           created: number
           metadata?: { [x: string]: unknown }
           type: "session.forked"
-          durable: { aggregateID: string; seq: number; version: 1 }
+          durable: { aggregateID: string; seq: number; version: 2 }
           location?: { directory: string; workspaceID?: string }
-          data: { sessionID: string; parentID: string; from?: string }
+          data: { sessionID: string; parentID: string; parentSeq: number; from?: string }
         }
       | {
           id: string
@@ -1339,9 +1351,9 @@ export type SessionLogOutput =
           created: number
           metadata?: { [x: string]: unknown }
           type: "session.instructions.updated"
-          durable: { aggregateID: string; seq: number; version: 1 }
+          durable: { aggregateID: string; seq: number; version: 2 }
           location?: { directory: string; workspaceID?: string }
-          data: { sessionID: string; text: string }
+          data: { sessionID: string; delta: { [x: string]: string | "removed" } }
         }
       | {
           id: string
@@ -4734,9 +4746,9 @@ export type EventSubscribeOutput =
       created: number
       metadata?: { [x: string]: unknown }
       type: "session.forked"
-      durable: { aggregateID: string; seq: number; version: 1 }
+      durable: { aggregateID: string; seq: number; version: 2 }
       location?: { directory: string; workspaceID?: string }
-      data: { sessionID: string; parentID: string; from?: string }
+      data: { sessionID: string; parentID: string; parentSeq: number; from?: string }
     }
   | {
       id: string
@@ -4823,9 +4835,9 @@ export type EventSubscribeOutput =
       created: number
       metadata?: { [x: string]: unknown }
       type: "session.instructions.updated"
-      durable: { aggregateID: string; seq: number; version: 1 }
+      durable: { aggregateID: string; seq: number; version: 2 }
       location?: { directory: string; workspaceID?: string }
-      data: { sessionID: string; text: string }
+      data: { sessionID: string; delta: { [x: string]: string | "removed" } }
     }
   | {
       id: string