Plan direct scenario drawing and ordered insertion milestone

harness/STATE.md

@@ -2,6 +2,14 @@
 
 ## Objective and phase
 
+Direct scenario work is now in isolated `codex/scenario-direct`, checkout
+`D:/CodexBuilds/Capella2-scenario-direct`, base ab661f2, dedicated target
+`D:/CodexBuilds/Capella2-scenario-target`. Scope and acceptance are recorded in
+release-scenario-editing.md. Existing scene/order semantics and typed drafts are
+retained; direct drawing, explicit insertion, same-parent reorder and correlated
+activation rendering are in implementation. Native input remains root-owned;
+this branch claims no native acceptance and does not close process/chain work.
+
 The first-release goal remains active and incomplete. Deliver usable Rust/Iced
 Operational Analysis and System Analysis/System Architecture, equivalent graphical,
 textual and REST semantics, artifact traceability, directly editable behavior,

harness/release-scenario-editing.md

@@ -0,0 +1,58 @@
+# Direct scenario editing — bounded implementation plan
+
+Status: implementation in the isolated `codex/scenario-direct` checkout, based on
+ab661f2. Native acceptance is pending the root's Windows/Linux trials. This does
+not complete the release or the separate process/chain gesture work.
+
+## Decisions
+
+Extend the existing `behavior::Scene`; retain its derived lifeline columns and
+ordered occurrence rows. No model/schema/layout records are added. Lifeline and
+occurrence UUIDs remain distinct from represented work and global exchanges.
+
+Select mode selects headers, stems, messages and occurrence boxes. A selected
+occurrence has a reorder handle; dragging it chooses a visible slot in its same
+parent sequence. It never reparents or changes lifeline columns. A Message tool
+uses the existing MessageStyle, with Call + correlated reply initially selected.
+Click-click or drag between represented lifelines captures a highlighted explicit
+insertion slot `(parent, before occurrence or append)` and opens the existing
+typed draft with those endpoints. Existing exchanges/calls are filtered against
+the complete candidate at that slot and shown through search plus 24-item pages.
+No compatible exchange produces an actionable retained draft, not a new global
+exchange or a silently changed endpoint. Timer remains available as a local tool.
+
+The canvas remains rendered while a bounded, independently scrollable form is
+open. Values keep the existing qualified-path editor and lifecycle. Final creation
+uses ordinary CreateElement plus SetSteps in one Batch; paired call/reply are
+inserted together and undo together. Reordering uses SetSteps within the captured
+parent. Existing core validation decides reply order, branch dominance, lifetime,
+phase and endpoint compatibility. Failed preparation/source writes retain drafts.
+
+Transient events capture document/scenario/revision/epoch, and the App validates
+the current Behavior owner before handling them. Selection does not invalidate a
+gesture within the same scenario. Escape, unfocus, context/tool change and pending
+drafts cancel gestures. Ordered pointer events and captured window positions avoid
+coalesced-click and changed-scroll-origin commits. No geometry is persisted.
+
+Execution bars derive their ends from actual correlated reply positions; separate
+conditional reply branches render their corresponding spans. Calls without a
+visible reply use a short explicitly open activation, not a fabricated reply.
+
+## Acceptance checks
+
+Production-event tests cover hit priority, click-click/drag, scroll-origin changes,
+Escape/unfocus/stale contexts and exactly one result per gesture. Planner/App tests
+cover middle/operand insertion, paired identities, complete SetSteps ordering,
+same-parent reorder, rejected reply-before-call, unchanged global exchanges, exact
+source/model Undo, draft retention and bounded exchange/call controls. Run focused
+and full desktop tests, strict all-target desktop Clippy and optimized build with
+the dedicated `D:/CodexBuilds/Capella2-scenario-target` target.
+
+Root native tasks (not yet performed):
+1. Draw an existing exchange again into the middle of a scenario as Call+Reply;
+   enter a qualified value, select both occurrences, Undo/Redo, save/reopen.
+2. Insert inside an ALT/LOOP operand, reorder within it, reject a reply before its
+   call, and inspect correlated execution bars and preserved occurrence identities.
+3. Cancel drawing after scrolling/layout change, retry, retain typed values while
+   navigation is blocked, and open/return from a referenced scenario. Verify at
+   1440x900 and 1100x700 on Windows and Linux before scoped acceptance.