D-19: Stream Inspector debug panel (⌘⌥R)

[kirich1409]

Description

Implement the debug panel that reveals the raw JSONL stream for the current Dialogue session — essential for reproducing parsing bugs, schema drift reports, and general support.

Spec: docs/architecture/dialogue-events.md §8 (Stream Inspector).

Scope

File

MacApp/Packages/AgentChatUI/Sources/AgentChatUI/Debug/StreamInspectorView.swift

UI

• Overlay sheet: 80% window height.
• Header: "Stream Inspector · {session_id short}" + buttons [Copy all] [Save .jsonl] [Pause capture] [Close].
• List: raw JSONL lines in arrival order; monospaced; JSON syntax-highlighted via simple regex tokenizer (keys, strings, numbers, booleans, nulls — using DS.Color.code* tokens).
• Per line: arrival timestamp, type + subtype badge, fold/unfold button, [Copy] button.
• Filter bar above list: type multiselect (system / assistant / user / result / stream_event), subtype text search, event-name search (within stream_event).
• Bottom meta: total events: N · bytes: K · unknown: M · parse_errors: P.

State store

StreamInspectorStore — actor holding circular buffer of 1000 raw events per session. API:

• append(rawLine: String, timestamp: Date) — called by ClaudeStreamJSONParser when it ingests each line.
• events() -> [StreamInspectorEntry] — snapshot for rendering.
• clear(), save(to: URL).

Populated during parsing (Wave 2 parser instrumented with a StreamInspectorHandle optional).

Persistence (optional, Settings-gated)

Settings → Advanced → Persist raw streams — when on, mirror to ~/Library/Caches/Relay/sessions/{session_id}.jsonl. Off by default.

Activation

• Keyboard: ⌘⌥R opens inspector for current session.
• Debug menu item.
• Accessible from DialogueView toolbar (secondary, small icon).

Acceptance Criteria

• Inspector opens on ⌘⌥R and shows the live stream of current session.
• Raw JSONL lines display in order, timestamped, JSON syntax-highlighted.
• Filters work: by type, subtype, event name.
• Copy all puts the entire session's JSONL on the clipboard.
• Save .jsonl writes to a file picker-chosen location.
• Pause capture freezes updates; unpause resumes.
• Settings toggle for persistence works; persistence file created when on.
• No measurable perf impact on session when inspector not open (buffer-only growth, no view cost).
• VoiceOver-navigable; keyboard-navigable.

Relationships

• Parent issue: EPIC: Dialogue — structured chat UI for agent sessions #250
• Blocked by: #D-8 (parser needs to feed the inspector handle)
• Blocks: #D-18 (integrate toolbar button)