test(fs-search): keep the glob-sampling fixture in canonical packed layout

The session-fixture-layout gate requires every session JSONL fixture in
the canonical packed layout (maximal delta runs per kind/block, as
migrate:packed-session-fixtures rewrites); the packChunks: false knob
violated that invariant and failed the snapshot job. Revert the knob and
canonicalize the recorded fixture instead: the live log's
eager-drain-packed rows migrate to the maximal-run layout a burst replay
reproduces, so the fixture stays replay-deterministic and canonical.

examples/acp-agent/tests/fs-search.cordis.yml

@@ -20,10 +20,6 @@
     model: deepseek-v4-pro
     persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
     persistenceCompression: !!js "process.env.DSH_SNAPSHOT === undefined ? 'zstd' : 'none'"
-    # Unpacked rows: the eager-drain batch boundaries that split packed delta
-    # runs are timing-dependent, so packed logs cannot replay-match a live
-    # record of a long reasoning stream.
-    packChunks: false
     workspaceContext: false
     skills:
       enabled: false