Add Discord and iMessage channel adapters

[Peyton-Spencer]

What changed

• adds a channel-adapter SPI and runtime registry backed by the existing supervised server
• exposes typed, authorization-scoped RPCs to list accounts, conversations, and messages and to send when a transport supports it
• adds a Discrawl adapter for local Discord status, guild/DM discovery, and archived message reads
• adds a macOS iMessage adapter for Messages database reads and AppleScript sends with Full Disk Access and Apple Events diagnostics
• adds focused adapter tests, including command-argument isolation for iMessage text

Capability and safety behavior

• Discrawl is explicitly archive-only: personal Discord sending fails with capability_unavailable
• bot and device Discord modes remain distinct transports; bot API sending is the next adapter, not a silent fallback
• iMessage is macOS-only, does not read history without Full Disk Access, and requires Apple Automation consent to send
• user message text is passed as an osascript argument, never interpolated into the AppleScript program
• no Ditto account or cloud sync is required

Current slice

This establishes the server/RPC vertical slice. It expects a locally available discrawl binary and uses the system sqlite3/osascript tools on macOS. Bundling/supervision, the SQLite normalized event/outbox store, bot transport, and unified inbox UI are intentionally follow-up layers.

Validation

• vp check (passes; repository has pre-existing warnings)
• vp run typecheck
• vp test run apps/server/src/channels/DiscrawlAdapter.test.ts apps/server/src/channels/IMessageAdapter.test.ts apps/server/src/dittoHarness/DittoHarnessRuntime.test.ts packages/contracts/src/settings.test.ts (64 tests)

Stack

Depends on #2, which depends on #1.

Note

Add Discord and iMessage channel adapters with ChannelRegistry and channels.* RPC endpoints

• Introduces ChannelAdapter interface and ChannelRegistry service that routes calls across registered adapters, with multi-account discovery and conversation aggregation when no accountId is given
• Implements DiscrawlAdapter for read-only Discord history via the Discrawl CLI (status, channels list, dms, messages); sendMessage always fails with capability_unavailable
• Implements IMessageAdapter for macOS iMessage via sqlite3 against chat.db for reads and osascript for sends; reports unavailable off macOS and permission_required when chat.db access fails
• Adds four WebSocket RPCs (channelsListAccounts, channelsListConversations, channelsListMessages, channelsSendMessage) with contract schemas in channels.ts and rpc.ts, plus authorization scopes in RpcAuthorization.ts: list endpoints require read scope, send requires operate scope
• Risk: iMessage send uses osascript with handle:-prefixed conversation IDs; verify argument escaping in IMessageAdapter.ts prevents injection. iMessage SQL query against chat.db requires Full Disk Access on macOS.

^{Macroscope summarized 1632af6.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ No successful main baseline artifact is available yet. This run establishes the initial measurement.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	—	13.5 KiB	—	15.1 KiB	✅
Codex	Thread snapshot wire	—	6.9 KiB	—	7.3 KiB	✅
Codex	Live turn WebSocket wire	—	6.6 KiB	—	7.8 KiB	✅
Codex	Live turn WebSocket decoded	—	57.0 KiB	—	66.4 KiB	✅
Codex	Live turn messages	—	11	—	21	✅
Claude	Total thread wire	—	13.5 KiB	—	15.1 KiB	✅
Claude	Thread snapshot wire	—	6.9 KiB	—	7.3 KiB	✅
Claude	Live turn WebSocket wire	—	6.6 KiB	—	7.8 KiB	✅
Claude	Live turn WebSocket decoded	—	57.9 KiB	—	66.4 KiB	✅
Claude	Live turn messages	—	11	—	21	✅

Baseline: unavailable · PR result: 1632af6 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.