feat(memory): preserve verbatim content the user explicitly asked to …

[im4codes]

…remember

The memory compression path summarises conversation events and can therefore drop exact user text — names, numbers, sentences the user flagged with an explicit "remember this" imperative were getting paraphrased or summarised into generic bullets in ## Key Decisions, then losing specificity further on each update cycle. Result: durable memory was missing content the user explicitly asked to preserve.

This is handled entirely in prompts — no language-specific keyword table, no regex gate. The compressor LLM already reads the user's messages; we just tell it to recognise the INTENT (cross-language: 记住/记得/记下/牢记, remember/keep in mind/note this, 覚えて, 기억해줘, recuerda, запомни, etc.) and route that content into a dedicated section.

• summary-compressor.ts buildCompressionPrompt: new ## User-Pinned Notes section in the structured template. Both the fresh-compression branch and the update-existing-summary branch carry an explicit VERBATIM PRESERVATION RULE telling the LLM: copy pinned content word-for-word, never paraphrase, translate, or truncate; carry it forward unchanged across every update.

• materialization-coordinator.ts extractDurableSignalsFromSummary: refactored to use a shared extractSummarySection helper (escaped-title regex) so any section can be pulled out. Now also scans ## User-Pinned Notes and pushes each non-empty line into the preferences bucket of DurableSignals. Effect: pinned content is automatically promoted to durable_memory_candidate instead of living only in the short-lived recent_summary, where it could eventually age out on rotation.

Existing summary-compressor + materialization tests remain green (25/25). The compressor tests don't assert on prompt text, so the change ships without touching test expectations.