feat(session): default JSONL writes to packed rows

.agents/notes/implemented/testing/2026-06-19-acp-snapshot-tests.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write
-2026-06-19-acp-snapshot-tests.md: b4cda8f32fe7a84a977bcbdbe5db0671cb9a7083
-2026-06-19-acp-snapshot-tests.zh.md: 5337c3852b524af4e8c556e93ec80084b30a6d0b
+2026-06-19-acp-snapshot-tests.md: 6e9f07cd65069423a61f94af44713054470395c6
+2026-06-19-acp-snapshot-tests.zh.md: 95c2ef6dd55d70202a9985c824c508c2dda42c00

.agents/notes/implemented/testing/2026-06-19-acp-snapshot-tests.md

@@ -20,7 +20,7 @@ A snapshot test boots the real ACP example, drives its stdio protocol from a det
 
 Each scenario's `session.jsonl` is harvested from a real run. `assistant/chunk` events reproduce the model streams; tool, message, and boundary events capture the harness behavior. One ordinary session artifact therefore serves as both replay source and behavioral expected output.
 
-When a scenario pins an alternative physical storage layout, its fixture is mechanically derived from a real unpacked counterpart. The scenario test requires every intended storage-row kind and exact event-for-event equality after decoding before the ordinary replay and log comparison proves that the assembled process consumes and reproduces that layout.
+Every committed session-format fixture uses the canonical packed physical layout. The all-row-kinds scenario is mechanically derived from an independent real recording; its test requires every packed storage-row kind and exact event-for-event equality after both fixtures decode, then ordinary replay and log comparison prove that the assembled process consumes and reproduces the layout.
 
 ### Replay derives the model script from the log
 
@@ -44,7 +44,7 @@ Replay is positional and therefore permits only one in-flight model stream per s
 
 ### Recording harvests the log; keyless replay needs a providerless config
 
-Recording runs the scenario with the real `llm-deepseek` adapter and the JSONL persistence backend configured with `persistenceCompression: 'none'`, then copies the produced `.jsonl` into the scenario dir. The explicit raw mode keeps committed replay fixtures line-readable while ordinary deployments use the backend's compressed default. Per-event appends are durable, but the harness shuts the subprocess down gracefully (close stdin → `await ctx.dispose()`) before harvesting so the final events are flushed. `llm-replay` itself does no recording — it is replay-only.
+Recording runs the scenario with the real `llm-deepseek` adapter and the JSONL persistence backend configured with `persistenceCompression: 'none'`, then copies the produced `.jsonl` into the scenario dir. The explicit raw mode keeps committed replay fixtures line-readable while ordinary deployments use the backend's compressed default; eligible chunk runs still use the default packed storage rows. Per-event appends are durable, but the harness shuts the subprocess down gracefully (close stdin → `await ctx.dispose()`) before harvesting so the final events are flushed. `llm-replay` itself does no recording — it is replay-only.
 
 Replay uses a `cordis.snapshot.yml` overlay that replaces the real adapter with `llm-replay` while retaining the live composition. Recording uses the ordinary config and a harness-supplied persistence root. Replay mode skips `.env` loading, so a stray API key cannot trigger a live call. See the [single-source config Agent Note](2026-07-04-single-source-acp-replay-config.md).
 
@@ -69,7 +69,7 @@ Tool determinism comes from a generated cwd, scrubbed environment, fresh non-log
 
 ### Two subcommands, replay in the default gate
 
-`pnpm run test:snapshot` replays committed fixtures keylessly; `test:snapshot:record` uses the real API and rewrites the harvested session log and stdout expected output. Missing fixtures fail loud. Every scenario carries `input.json`, `stdout.expected.jsonl`, and `session.jsonl`; no-model cases use a header-only log. `replay.override.json` is required only for scenarios marked `overridden`, because its presence replaces derived replay. Fixture guards reject missing, mismatched, and orphaned files. Both commands accept scenario filters.
+`pnpm run test:snapshot` replays committed fixtures keylessly; `test:snapshot:record` uses the real API and rewrites the harvested session log and stdout expected output. The same keyless gate discovers repository JSONL by its `session` header and rejects any fixture that differs from the shared codec's canonical packed representation. Missing fixtures fail loud. Every scenario carries `input.json`, `stdout.expected.jsonl`, and `session.jsonl`; no-model cases use a header-only log. `replay.override.json` is required only for scenarios marked `overridden`, because its presence replaces derived replay. Fixture guards reject missing, mismatched, and orphaned files. Both commands accept scenario filters.
 
 ## Alternatives considered
 

.agents/notes/implemented/testing/2026-06-19-acp-snapshot-tests.zh.md

@@ -20,7 +20,7 @@ Status: implemented
 
 每个场景的 `session.jsonl` 都从真实运行中采集。`assistant/chunk` 事件复现模型流；工具、消息和边界事件捕获 harness 行为。因此，一份普通会话产物同时充当重放来源和行为预期输出。
 
-当场景固定另一种物理存储布局时，其 fixture 会从真实的未打包对应项机械派生。场景测试要求包含每一种预期存储行类型，并在解码后逐事件精确相等；随后，普通重放与日志比较才会证明组合后的进程能够消费并复现该布局。
+每个签入仓库的会话格式 fixture 都使用规范的打包物理布局。覆盖所有行类型的场景从一份独立的真实录制机械派生；测试要求它包含每一种打包存储行类型，并在两份 fixture 解码后逐事件精确相等；随后，普通重放与日志比较会证明组装后的进程能够消费并复现该布局。
 
 ### 回放从日志推导模型脚本
 
@@ -44,7 +44,7 @@ Status: implemented
 
 ### 录制采集日志；无密钥回放需要无提供方的配置
 
-记录模式使用真实 `llm-deepseek` 适配器和配置为 `persistenceCompression: 'none'` 的 JSONL 持久化后端运行场景，再把生成的 `.jsonl` 复制到场景目录。显式 raw 模式让已提交重放 fixture 保持逐行可读，而普通部署使用后端的压缩默认值。逐事件追加具有持久性，但 harness 会在采集前优雅关闭子进程（关闭 stdin → `await ctx.dispose()`），以确保最终事件已刷出。`llm-replay` 本身不执行记录——它只负责重放。
+记录模式使用真实 `llm-deepseek` 适配器和配置为 `persistenceCompression: 'none'` 的 JSONL 持久化后端运行场景，再把生成的 `.jsonl` 复制到场景目录。显式 raw 模式让已提交重放 fixture 保持逐行可读，而普通部署使用后端的压缩默认值；符合条件的分片连续段仍使用默认的打包存储行。逐事件追加具有持久性，但 harness 会在采集前优雅关闭子进程（关闭 stdin → `await ctx.dispose()`），以确保最终事件已刷出。`llm-replay` 本身不执行记录——它只负责重放。
 
 重放使用 `cordis.snapshot.yml` overlay，以 `llm-replay` 替换真实适配器，同时保留实时组合。记录使用普通配置和由 harness 提供的持久化根目录。重放模式跳过 `.env` 加载，因此意外存在的 API 密钥不会触发实时调用。参见[单一来源配置 Agent Note](2026-07-04-single-source-acp-replay-config.md)。
 
@@ -69,7 +69,7 @@ Status: implemented
 
 ### 两个子命令，回放在默认门禁中
 
-`pnpm run test:snapshot` 无需密钥即可重放已提交 fixture；`test:snapshot:record` 使用真实 API，并重写采集的会话日志与 stdout 预期输出。缺少 fixture 时会响亮失败。每个场景都包含 `input.json`、`stdout.expected.jsonl` 和 `session.jsonl`；不调用模型的情况使用仅有请求头的日志。只有标记为 `overridden` 的场景才需要 `replay.override.json`，因为它一旦存在就会取代派生重放。Fixture 守卫会拒绝缺失、不匹配和孤立文件。两个命令都接受场景过滤器。
+`pnpm run test:snapshot` 无需密钥即可重放已提交 fixture；`test:snapshot:record` 使用真实 API，并重写采集的会话日志与 stdout 预期输出。同一无密钥门禁会通过 `session` header 发现仓库中的 JSONL，并拒绝与共享编解码器的规范打包表示不同的任何 fixture。缺少 fixture 时会响亮失败。每个场景都包含 `input.json`、`stdout.expected.jsonl` 和 `session.jsonl`；不调用模型的情况使用仅有请求头的日志。只有标记为 `overridden` 的场景才需要 `replay.override.json`，因为它一旦存在就会取代派生重放。Fixture 守卫会拒绝缺失、不匹配和孤立文件。两个命令都接受场景过滤器。
 
 ## 曾考虑的替代方案