[Bug] Runtime repair passes only transcript tail — full session history is dropped from new context

Summary

When MiniMax Code repairs a session (after daemon restart, idle timeout, OOM, or mode switch), the new runtime receives only the last ~4 messages in its <visible-transcript> block. The full conversation history exists on disk but is not loaded into the new context — the model loses awareness of the original task, scope, and prior decisions, and may believe it never received the task at all.

This is not an LLM-summarization failure. The summarization mechanism (session_context_epoch) exists but is never triggered, because the repair path bypasses it entirely.

Environment

• MiniMax Code (Electron) on macOS
• Observed session at time of repair: 513 messages, 2.2 MB on disk
• OpenCode DB: ~/.local/share/opencode/opencode.db
• Mavis DB: ~/.mavis/sqlite.db

Reproduction

1. Run an ongoing session with significant context.
2. Trigger a runtime repair (daemon restart, OpenCode crash, long idle, etc.).
3. Inspect the <visible-transcript> block delivered to the new session.

Expected

The repaired session reconstructs full context — either by injecting the complete session_messages history, by running session_context_epoch summarization, or by restoring from $MAVIS_SCRATCHPAD.

Actual

Only the last ~4 messages are passed. No summary, no history injection, no scratchpad restore.

Findings

• ~/.mavis/sqlite.db.session_messages retains the complete history (513 messages / 2.2 MB in the observed case). The data is on disk — it's just not loaded.
• ~/.local/share/opencode/opencode.db.session_context_epoch exists with a proper schema for LLM summarization (baseline, snapshot, baseline_seq, replacement_seq), but the table is empty — the mechanism never ran in observed sessions.
• The session was far below the LLM-context limit, so summarization was never triggered organically either.
• Conclusion: "context loss after repair" is the repair path skipping both summary and history-injection. Not a token-limit issue, not an LLM-summary quality issue.

No repository files or tests are named. Start by locating the runtime repair path that constructs the block, then inspect how ~/.mavis/sqlite.db.session_messages and the session_context_epoch table are read. Done means a repaired session restores full history or an available summary, with the original task and prior decisions preserved.