perfect target area thing

docs/clipboard-plan.md

@@ -30,10 +30,11 @@ stage and timeline. A stage marquee replaces, or with Shift adds to, the same
 set. Timeline rows, bars, and cel blocks render membership from that same set;
 the primary member gets the inspector/focus treatment.
 
-Targeting remains separate. Clicking a timeline label both selects it and aims
-it. Shift-click changes the selection set and makes the clicked row the one
-target. Clicking a bar/cel or the stage changes selection without silently
-changing the target. A target is singular even when selection is plural.
+Creation targeting is derived rather than stored. The primary (last-selected)
+occurrence is the preferred row; the playhead validates it and, when necessary,
+walks outward to the nearest valid containing occurrence. A target is singular
+even when selection is plural. See `docs/creating-in.md` for the resolver
+contract.
 
 ## Clipboard value
 
@@ -50,19 +51,13 @@ cross-project identity collision policy hidden inside it.
 
 ## Paste
 
-Paste always uses the explicit insertion target and the playhead:
-
-- no target: paste at the top of the open symbol;
-- aimed ordinary node: paste beside it in the symbol that owns it;
-- aimed instance, including an instance whose source is drawn as a lane: paste
-  inside the symbol it places;
-- the open lane's own row: paste directly into that lane.
-
-The destination is resolved structurally from the target. It does not require
-the target instance to be visible at the playhead. Being outside the target
-symbol's authored window is legal: content can exist there and be cropped by
-the window. Lane paste may grow the lane/window because a sequence cannot store
-an overlapping or unreachable tail and pretend the edit succeeded.
+Paste resolves one destination from the primary selection and playhead. An
+ordinary occurrence is usable only while the playhead maps through every
+enclosing occurrence and lies within its extent. Otherwise resolution walks
+outward, with the open symbol as the total fallback. A selected lane is an
+insertion surface only while all occurrences enclosing its parent symbol are
+valid. Multi-selection supplies one ordered payload, not several destinations;
+only its primary member anchors this resolution.
 
 The earliest finite start among the copied roots is aligned with the playhead
 in the destination. All other root starts retain their offset from it. Roots
@@ -118,13 +113,14 @@ After either duplicate command, the new roots replace the selection.
 
 Cut, paste, duplicate, and duplicate unique each call one domain command and
 commit through one `edit/transaction`; each is exactly one undo/redo step no
-matter how many nodes or symbols it touches. Copy, aiming, and selection do not
+matter how many nodes or symbols it touches. Copy and selection do not
 touch history. A refusal changes no document leaves and creates no history step.
 
 Undo/redo filters the complete selection set against the restored document and
 repairs the primary selection. Clipboard payloads remain snapshots. Paste
-validates the destination and all remapped references at commit time, so a stale
-target or a newly impossible symbol cycle refuses rather than partially editing.
+validates the resolved destination and all remapped references at commit time,
+so a stale selection or a newly impossible symbol cycle refuses rather than
+partially editing.
 
 ## Required tests
 
@@ -133,7 +129,7 @@ normal shared references, deep unique graph remaps, multi-root relative timing,
 composition overlap, lane overwrite, lane forward duplication and ripple,
 mixed-owner duplication, cycle refusal, stale targets, and all-or-nothing
 failure. Event tests cover copy without history, atomic cut/paste/duplicates,
-resulting multi-selection, target resolution, pasting beyond a symbol window,
+resulting multi-selection, target fallback at the playhead,
 and one undo plus redo of each mutation. Browser tests cover mirrored stage and
-timeline selection, Shift-toggle on labels/bars/cels, singular aiming, and the
-keyboard commands.
+timeline selection, Shift-toggle on labels/bars/cels, singular derived creation
+targeting, and the keyboard commands.