v0.7.0 — DisC Studio becomes a design-review tool

DisC Studio becomes a design-review tool: point it at an existing
Java/Spring project and it derives the current design from your code, shows a
before/after diff of the change under review, and blocks sign-off if the
proposed design would silently drop calls that exist today. Handing the design
to the DisC plugin to generate tests + code is included but experimental —
the design-review path is the verified one.

Added

• Code→design derivation. A deterministic projection of a Java entry
  method's call flow into a sequence diagram (POST /api/code-derive,
  /api/code-derive-by-path): same code in, same diagram out; a small edit
  makes a small diagram change. Resolves through an interface to its
  implementing class, so the derived flow is the real one, not an empty stub.
• Step 3 is a design diff. Sign-off shows before (your code's current
  flow, or a greenfield banner) beside after (the proposed design), plus a
  plain-language "why this design" from the analyzer's variance plan.
• Dropped-call gate. If the proposed design removes a call that exists in
  the current code, Step 3 lists it and blocks team sign-off until the removal
  is explicitly acknowledged — catching silent behaviour regressions before
  any generation.
• Update-mode grounding. When the story names an existing class
  ("Update X"), that class's current flow is injected into analysis so the
  design preserves calls the acceptance criteria never mention; a chip under
  the story box shows whether the name matched (and hints on near-misses).
• Code→design diff pipeline (dev harness at code-diff.html): a ticket +
  code → minimal design delta (new variant behind a resolver / rule-table),
  with a before/after view and a deterministic test-cost rationale.
• Abort a running analysis — the Analyze banner gains an Abort action that
  stops the in-flight LLM chain and kills the subprocess.

Changed

• Story and acceptance criteria are entered together in one Step-2 box;
  Gherkin lines parse into criteria automatically.
• disc.claude.effort defaults to medium; subprocess timeout raised to 600s.
• A one-variant "family" is refused with a question instead of generating an
  abstraction with nothing to choose.

Requires

• The DisC plugin v0.11.1+ (validate no longer false-refuses correct
  designs). Install/update: /plugin marketplace update mossgreen-design-is-code.