fix: broadcast uses summaryForStore to support salvaged summaries (#1718)

syncAndBroadcastSummary was using the raw ParsedSummary (null when salvaged)
instead of summaryForStore for the SSE broadcast, causing a crash when the
LLM returns <observation> without <summary> tags. Also removes misplaced
tree-sitter docs from mem-search/SKILL.md (belongs in smart-explore).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/services/worker/agents/ResponseProcessor.ts

@@ -354,12 +354,12 @@ async function syncAndBroadcastSummary(
     id: result.summaryId,
     session_id: session.contentSessionId,
     platform_source: session.platformSource,
-    request: summary!.request,
-    investigated: summary!.investigated,
-    learned: summary!.learned,
-    completed: summary!.completed,
-    next_steps: summary!.next_steps,
-    notes: summary!.notes,
+    request: summaryForStore!.request,
+    investigated: summaryForStore!.investigated,
+    learned: summaryForStore!.learned,
+    completed: summaryForStore!.completed,
+    next_steps: summaryForStore!.next_steps,
+    notes: summaryForStore!.notes,
     project: session.project,
     prompt_number: session.lastPromptNumber,
     created_at_epoch: result.createdAtEpoch