fix(mcp): settle digest responses must retain refs for auto-pinning

[cursor]

Follow-up from PR #1106 / #1101 code review. MCP ref auto-pinning breaks when responseLevel: digest is used with --settle.

Problem

interactionSettleView (digest level) drops settle.diff.lines and keeps only summary, but mergeSettleIssuedRefPins collects refs exclusively from lines. MCP clients receive settle.refsGeneration but never record pins for added-line refs, so the next @ref command goes out unpinned and stale-ref warnings return.

Snapshot digest already solved this: snapshotView retains a capped refs: [{ ref, label }] array when dropping node payloads (src/daemon/response-views.ts). Settle digest does not mirror that pattern.

Suggested fix

1. In interactionSettleView, when dropping line texts at digest level, add a capped refs array from added diff lines (refs only, like snapshot digest).
2. Update mergeSettleIssuedRefPins / readIssuedRefBodies to read settle.refs (or equivalent) when lines are absent.
3. Add test: MCP merges digest-level settle refs too (analogous to existing MCP merges digest-level snapshot refs too in command-tools.test.ts).

Acceptance

• press --settle with responseLevel: digest → subsequent press @<newRef> is auto-pinned with ~s<refsGeneration>.
• Default response level behavior unchanged.

Context

• Parent: press/click/fill --settle: settled observation in the interaction response #1101
• Open PR: feat: --settle returns the settled diff in the interaction response (#1101) #1106
• Code: src/daemon/response-views.ts, src/mcp/command-tools.ts

[thymikee]

Resolved by merged #1106. Current main includes commit 24663fe4 (fix: preserve settle digest refs for mcp): interactionSettleView keeps capped added refs at digest level, mergeSettleIssuedRefPins reads settle.refs when lines are absent, and src/mcp/__tests__/command-tools.test.ts has MCP merges digest-level settle refs too, including never-settled diffs. Closing.