crabidy/plan/queue-register.md

Plan — queue selection, visual mode, and the register

Executes architecture/queue-register.md against quality/queue-register.md. Ordered by dependency. Three commits: (A) the shared mark/visual trait with the library moved onto it, (B) queue marks + the register in cbd-tui, (C) cbd-web parity + docs.

No server work: Remove already takes many positions and Insert takes a path list (G25).

A — Shared mark and visual behaviour (cbd-tui)

• A1 — Fill in MarkedPane in app/list.rs: toggle_visual, toggle_mark, toggle_mark_view, paint_between, selection — moved verbatim in behaviour from library.rs, with the markable gate taken from the implementor. Verifies: G11, G12, G16.
• A2 — impl MarkedPane for Library, deleting the now-duplicated inherent methods and keeping get_selected as a thin wrapper over selection so existing call sites are untouched. markable = is_queable. Verifies: the existing library visual-mode suite passes unchanged (G11, G12).
• A3 — carry_marks in app/list.rs: greedy in-order path match, drop marks whose track is gone, all-false when nothing matches, tolerant of a short old_marked. Verifies: the ten carry_marks_tests (G2, G3).
• A4 — Commit A. Merged into commit B: group A alone leaves carry_marks and Register unwired, and committing dead code for the next commit to use is worse than one larger commit. The extraction is still proven behaviour-preserving — the library's whole visual-mode suite passes untouched.

B — Queue marks and the register (cbd-tui)

• B1 — impl MarkedPane for Queue with markable = always, and a visual: Option<usize> field on Queue. Verifies: G12.
• B2 — update_queue carries marks through carry_marks instead of rebuilding them as false: keep the previous path list and mark flags, reconcile, apply. Verifies: G1, G2.
• B3 — Register::set (replace the todo!()) and an App.register field. Verifies: the register suite (G6, G10).
• B4 — y in both panes. New Action::LibraryYank and Action::QueueYank; each takes selection(), writes the register, and clears the marks it consumed. Verifies: G5, G14, G15.
• B5 — d in the queue deletes every marked row (cursor row when none), writing them to the register first, in one RemoveTracks call with positions from the current list. Replaces the FIXME. Verifies: G1, G13, G14, G15.
• B6 — c/C fill the register with the tracks they drop (C everything, c everything but the current track). Verifies: G4.
• B7 — p/P paste the register. Action::QueuePaste / QueuePasteBefore send InsertTracks(register.paths(), pos) with pos = cursor + 1 for p, cursor for P; a no-op on an empty register; the register survives. QueueInsertHere's old cross-pane behaviour is gone. Verifies: G7, G8, G9.
• B8 — Queue visual mode in dispatch. A queue_move wrapper mirroring library_move, and the visual auto-leave guard generalized to whichever pane is in visual mode with its own movement whitelist. Verifies: G11.
• B9 — Bindings + help. Queue scope gains s, v, V, y, P; library gains y; p's description changes. The help modal derives from BINDINGS, so it follows. Verifies: G19, G20.
• B10 — Status feedback. The pane title shows — VISUAL in the queue as in the library, and a non-empty register is visible somewhere (title or now-playing line) so paste is not blind. Verifies: G22 in spirit; keeps G9's no-op explicable.
• B11 — Dispatch tests for the gates named above. Verifies: G1, G4, G5, G7–G9, G13–G15.
• B12 — Commit B with the whole cbd-tui suite, clippy -D warnings, and fmt clean (G24, G26).

C — cbd-web parity and docs

• C1 — Register + carry_marks in cbd-web/src/state.rs, same shape and same test cases as the TUI's. Verifies: G17, G18.
• C2 — Library visual mode (the piece deferred when v/V landed in the TUI): visual: Option<usize> on LibraryPane, the same anchored paint, Action::LibraryVisualMode on v/V, auto-leave on non-movement. Verifies: G17.
• C3 — Queue marks beside the signal. The web queue owns no list, so hold marks: Vec<bool> plus the path list they were taken against, and reconcile on each Queue update. Verifies: G18.
• C4 — Queue actions: QueueToggleMark, QueueVisualMode, QueueYank, QueuePaste, QueuePasteBefore, plus d/c/C writing the register — same semantics as the TUI. Verifies: G17.
• C5 — Keymap + HELP table rows for all of the above, keeping the lockstep test green; clickable equivalents where the web client has them. Verifies: G19.
• C6 — Verify the web half properly: clippy for native and wasm32-unknown-unknown, cargo test -p cbd-web, and a trunk bundle build. Verifies: G26.
• C7 — Docs. docs/src/clients/tui.md (key table + a register section), docs/src/clients/web.md, docs/src/queue.md (what the register is and is not), and the README usage section. State plainly that p changed meaning. Verifies: G21, G22, G23.
• C8 — plan/summary.md entry, then commit C.

Deferred (recorded, not dropped)

• Named registers ("a) — Register is shaped for it; not built.
• A numbered/history register stack, and any cross-client or persistent register.
• A per-entry queue id in the proto, which would make mark reconciliation exact instead of a greedy path match.