Compaction rendering has split ownership between condition strip, semantic stream, and committed rows

[Juliusolsson05]

Problem

Compaction has three disconnected render paths that can disagree:

1. Out-of-feed condition strip from claude.compaction.
2. Live semantic placeholder gated by turn.isCompactionSynthesis.
3. Committed compact boundary/summary rows after transcript entries arrive.

In saved bundles, the condition can say compaction is running while the feed renders raw semantic synthesis text.

Evidence

Bundle:

~/.config/agent-code/debug-bundles/manual/2026-06-22T12-42-54-045-c973322e

• claude.compaction condition is visible/running.
• proxy-semantic.json.currentTurn.text starts with <analysis>.
• The semantic turn lacks isCompactionSynthesis.

Relevant Paths

• src/renderer/src/workspace/tile-tree/TileLeaf/CompactionStrip.tsx
• src/renderer/src/workspace/tile-tree/TileLeaf.tsx
• src/renderer/src/features/feed/ui/rows/CompactBoundaryRow.tsx
• src/renderer/src/features/feed/ui/rows/CompactSummaryRow.tsx
• src/renderer/src/features/feed/ui/semantic/StreamingTurn.tsx
• src/renderer/src/features/feed/model/renderModel.ts

Expected

There should be one ownership rule for compaction rendering. If any reliable signal says compaction is active, raw synthesis content should be suppressed in the feed.

[Juliusolsson05]

Linking this back to #172. This issue is directly about render ownership: compaction currently has separate condition-strip, semantic-stream, and committed-row render paths that can disagree.

The #172 rendering engine work should give compaction a single owner in the ordered feed plan. After #172 lands, this issue should be re-tested and either closed as covered or narrowed to any remaining provider-specific compaction signal problems.