fix(tui,host): project the human transcript from append-origin events

The terminal and history pagination both treated the model-visible surface as
the human transcript. A landed compaction replacement therefore erased the
conversation it summarized — messages the reader had already seen — and a
model-only replacement copy consumed a page's `maxMessages` quota, which could
also split a compaction's provenance from the replacement citing it.

`dsh-session` now exports the marker split `isAppendSurfaceEvent` /
`isReplacementSurfaceEvent`. The terminal replays append-origin surface events,
keeps a shadowed step's tool cards paired through its append-origin assistant
message, and renders one dim marker where a compaction landed; the checkpoint is
recognized through the compaction seam's `isCompactCheckpointSource` contract,
not the shape of the replacement. `session.history` counts only append-origin
human messages. Everything model-facing keeps reading `session.surface`.

pnpm-lock.yaml

@@ -4987,6 +4987,9 @@ importers:
       '@deepseek-ai/dsh-commands':
         specifier: workspace:^
         version: link:../commands
+      '@deepseek-ai/dsh-compact':
+        specifier: workspace:^
+        version: link:../../compact/compact
       '@deepseek-ai/dsh-goal':
         specifier: workspace:^
         version: link:../../goal/goal