Checkpoint source 7 workflows and in-progress diagram authoring redesign

Preserve current core, source, REST, desktop, recovery, documentation and validation work, including AGENTS.md and the development summary. This is a work-in-progress checkpoint: the new compact palette has outstanding compilation errors and native acceptance; earlier passing gates retain their documented scope.

README.md

@@ -86,7 +86,7 @@ In the state view, **Select / move** drags vertices and containers without repar
 **Textual model** has a source-file folder tree, per-file drafts, syntax highlighting, live linting and explicit **Apply all**. Collapse/Locate navigate the hierarchy; collapsed folders retain draft and diagnostic indicators. Right-click a file for contextual actions. Projects can use relative includes to organize source into files. For example:
 
 ```text
-arcadia 6;
+arcadia 7;
 project harbor "Harbor assistance" {
     oa_entity control "Harbor control" {}
     oa_activity respond "Respond to requests" {
@@ -153,7 +153,7 @@ To preserve authored files and comments, use `POST /api/v1/projects/import-sourc
 
 ## Development
 
-The 2026-09-06 source-6 verification accounts for **943 passing tests and one existing ignored benchmark** across the full workspace run and complete affected-suite reruns after three compatibility-expectation corrections. The **48 HTTP tests** are included in that coverage, not additional to it. Source-6 OpenAPI validation passes 39 fixtures and checks 197 component schemas. [Current state](harness/STATE.md) identifies the exact logs and outstanding checks; this evidence does not claim one uninterrupted green workspace run or accept subsequent edits. Fresh GUI/server builds, strict checks for the final tree, source-6 native workflows, Linux/MSRV verification and current release packages remain release gates.
+Source7 integration adds caller-qualified reusable-process links and explicit interface-operation identity. Its [contract decision](harness/release-source7-integration-decision-20260906.md) and [current state](harness/STATE.md) distinguish prepared code from tested behavior. Current OpenAPI validation passes72structural fixtures across204schemas; source7 core, desktop, HTTP, recovery and native acceptance remain separate gates. Earlier source6 Windows and Linux results retain their exact recorded revision scope. Final full suites, strict checks, optimized/MSRV builds and current release packages are still required.
 
 ```sh
 cargo fmt --all -- --check