outl: Command for Claude Code

You want to add Op::$1 to the outl tree CRDT. MANDATORY checklist:

1. Define the variant in crates/outl-core/src/op.rs

$1 {
    node: NodeId,
    // ... op fields
    // CRITICAL: include `old_*` fields for undo.
    // Without old_*, undo_op cannot revert.
}

2. Implement do_op in crates/outl-core/src/tree/op.rs

• Fill old_* in the LogOp before applying the mutation.
• If the op can violate an invariant (cycle, etc), check first and treat as a no-op on materialization (but the op still goes to the log).

3. Implement undo_op

• Revert using the old_* fields of the LogOp.
• Idempotency: undo of an op that was never applied must be a no-op.

4. Update serialization

• Verify that serde derive already covers it. If there's a binary field, ensure base64 or bincode.
• Add conversion to the SQLite schema in storage/sqlite.rs if the op has extra fields.

5. Mandatory tests (in crates/outl-core/tests/)

• Convergence: 3 replicas apply the op in different orders → same final state.
• Idempotency: applying 2x = applying 1x.
• Reordering: a late-arriving op forces a correct undo/replay.
• Interaction with Move: an op concurrent with a Move on the same node converges.

6. Document in docs/crdt.md

• Add a paragraph in the "Operations" section describing semantics.
• Add a concurrent example if the op has non-obvious interactions.

7. Reaching the clients

An Op a user can trigger needs a way to trigger it, and that path is declared, not hand-rolled:

• Action + capability. Add the Action to outl-shortcuts; support() is an exhaustive match, so it will not compile until all three clients state what they do with it (root CLAUDE.md invariant 12).
• The command. Body in outl-tauri-shared/src/commands/, one entry in the matching *_commands! list in src/wrappers/catalog.rs, then an invoke_handler! entry in both clients. Never hand-write the #[tauri::command] wrapper. Shared bodies take String, not &str.
• The mutation. Route it through outl_actions::commit_page so the undo snapshot, backlink invalidation, peer announce and projection all happen, in order.
• The wire shape. If the reply carries a new DTO, mirror it in crates/outl-frontend-shared/src/api/types.ts and pin it in outl-tauri-shared/tests/wire_types.rs.
• The TUI. It still derives ops from rendered markdown (issue 263), so a new op reaches it through outl-actions, not through save_page_with.