[T2.3] Harden card grouping and rounded-stack rules

[DeliciousBuding]

Task: T2.3 - Harden card grouping and rounded-stack rules

Phase: 2 - Shared Chat Timeline Hardening
Priority: P0 | Size: M | Lane: B
S.U.P.E.R Drivers: S,R
Test Expectation: Shared render/CSS tests plus Desktop Playwright geometry
Memory/Governance Impact: None

Description

Make related tool/approval/preview cards visually merge cleanly without collapsing unrelated cards.

Acceptance Criteria

• Consecutive related cards align in one stack
• Inner radii collapse and outer radii remain
• Regression tests prove no horizontal overflow
• Passes S.U.P.E.R Quick Check for: S,R
• Satisfies test expectation: Shared render/CSS tests plus Desktop Playwright geometry
• Updates resolved memory or instruction surfaces if durable project knowledge or agent instructions changed

Affected Files

• app/shared/src/chatview/components/

Dependencies

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

---

Managed by Spec-Driven Develop workflow

[DeliciousBuding]

Post-task telemetry for T2.3 / PR #404

• actual_effort: M
• s.u.p.e.r_score: 4/5
• unplanned_dependencies: 0
• merged_pr: fix(chat): harden card stack radii #404
• merge_commit: d3daee8
• evidence_level: fixture-unit + playwright-ui + visual-qa
• real_tested: false
• gates: shared rendering/CSS contract tests, Desktop/Web chat-flow E2E, Desktop/Web visual chat-flow, shared tests, Desktop/Web typecheck, CI checks workflow success
• boundary: does not claim packaged Desktop, real login, real Hub/Edge runtime, real CLI/model/API, installer, signing, or production release

[DeliciousBuding]

Closed after PR #404 merged into dev/delicious233 at d3daee8. real_tested=false; evidence is fixture-unit + playwright-ui + visual-qa.