[T2.1] Add golden mixed-source transcript fixtures

[DeliciousBuding]

Task: T2.1 - Add golden mixed-source transcript fixtures

Phase: 2 - Shared Chat Timeline Hardening
Priority: P0 | Size: M | Lane: A
S.U.P.E.R Drivers: U,P,R
Test Expectation: Shared Vitest golden tests
Memory/Governance Impact: None

Description

Add mixed Hub/Edge/user/tool/subagent/markdown fixtures that prove deterministic transcript ordering.

Acceptance Criteria

• Hub user, Edge tool call/result, agent reply, subagent detail, and markdown table order is deterministic
• Inspector-only details do not enter main transcript
• Fixture is reusable by Desktop/Web E2E where useful
• Passes S.U.P.E.R Quick Check for: U,P,R
• Satisfies test expectation: Shared Vitest golden tests
• Updates resolved memory or instruction surfaces if durable project knowledge or agent instructions changed

Affected Files

• app/shared/src/transcript/
• app/shared/src/chatview/

Dependencies

• Depends on: See docs/plan/dependency-graph.md

---

Managed by Spec-Driven Develop workflow