D-4: Commit Dialogue spec to docs/architecture/

[kirich1409]

Description

Commit the Dialogue research report summary and the events specification to docs/architecture/ as the long-term source of truth. Research was produced in a worktree under swarm-report/ (gitignored); this task lifts the authoritative portions into version-controlled documentation.

Spec: Epic #250 §13 (References).

Scope

Create two new files in docs/architecture/:

1. docs/architecture/dialogue.md

Condensed architectural summary — copy of Epic #250 §1–§11 with minor adaptations:

• Problem statement, user stories, naming rationale
• Package diagram and dependency graph
• Session surface model (SessionSurface, Presentation enum)
• Cross-surface resume semantics (claude --resume <session_id>)
• Live-feel UX principles
• External dependencies decisions (swift-markdown chosen, Textual rejected with rationale)
• Risk register and MVP acceptance criteria
• Out-of-MVP deferral list
• Post-MVP path to server-side / ACP topologies

2. docs/architecture/dialogue-events.md

Full event catalog with wire-level detail. Source: swarm-report/chat-mode-spec-events.md from research worktree, verbatim with header matched to project docs style.

Update cross-references:

• Add entry to CLAUDE.md → Architecture Documents section: docs/architecture/dialogue.md, docs/architecture/dialogue-events.md.
• Link dialogue.md from docs/architecture/relay-cloud-architecture.md if that file has an index.

Acceptance Criteria

• docs/architecture/dialogue.md exists and covers §1–§11 of epic spec.
• docs/architecture/dialogue-events.md exists with full event catalog + wire schema for every documented event type.
• CLAUDE.md Architecture Documents section lists both new files.
• All code snippets in docs use syntax fences with language markers for future syntax highlighting.
• No content duplicated between epic body and docs — epic references docs, docs are source of truth.

Relationships

• Parent issue: EPIC: Dialogue — structured chat UI for agent sessions #250
• Blocks: D-7 (AgentChat package — implementer reads from spec), D-8 (parser — reads event schema), D-10 (reducer — reads dedup invariants)
• Related: research worktree .worktree/research-chat-mode (source of truth before commit)