[BUG] Context silently wiped after "Connection error" during streaming fallback

Found 3 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/17072
2. https://github.com/anthropics/claude-code/issues/17549
3. https://github.com/anthropics/claude-code/issues/17711

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🤖 Generated with Claude Code

● I'm experiencing what appears to be the same underlying issue but with a different symptom.

The issue: PostToolUse hooks display "(1/2 done)" despite both hooks completing successfully #16273

My environment: Claude Code 2.1.5, WSL2, Opus
Same error chain:
Error streaming, falling back to non-streaming mode: Connection error.
Error in non-streaming fallback: Request was aborted.

Different outcome: Instead of crashing, my context is silently wiped - goes from ~86k tokens to ~2k. Session continues but all conversation history is lost. Debug logs show
suspicious Summarizing all X messages (~0 tokens) entries suggesting context is already empty when this triggers.

Before:
❯ /context
⎿ Context Usage
⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ claude-opus-4-5-20251101 · 86k/200k tokens (43%)

After (following connection error + Esc):
❯ /context
⎿ Context Usage
⛁ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ claude-opus-4-5-20251101 · 2k/200k tokens (1%)

Debug log sequence:
2026-01-11T17:18:59.766Z [DEBUG] Summarizing all 5 messages (~0 tokens)
2026-01-11T17:19:00.439Z [ERROR] Error streaming, falling back to non-streaming mode: Connection error.
2026-01-11T17:19:02.262Z [DEBUG] Summarizing all 6 messages (~0 tokens)
2026-01-11T17:19:28.064Z [ERROR] Error streaming, falling back to non-streaming mode: Connection error.
2026-01-11T17:19:42.879Z [DEBUG] Streaming aborted by user: Request was aborted.
2026-01-11T17:19:42.879Z [ERROR] Error in non-streaming fallback: Request was aborted.

This may be a different code path hitting the same fallback failure, or the same bug with slightly different recovery behavior between versions. The silent context wipe is arguably more
dangerous than a crash since you don't realize it happened until you check /context.

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