refactor(agents): let Claude and Codex read the community through a host interface

[loganj]

🤖

Summary

• Second of three PRs that let a Buzz agent run without the desktop app open (see Why). Stacked on refactor(agents): separate the agent runner and its reads from the desktop app #961.
• Before an agent answers, the Claude and Codex code reads the channel, the recent conversation, people's names and the agent's saved memory. Today it gets all of this from the owner's signed-in session inside the app. A program outside the app has no such session.
• Now this code asks for those reads through one small interface. The app fills the interface from the owner's session, exactly as before, so nothing changes in the app. The standalone program in feat(agent-host): run a saved agent without the desktop app #967 fills it by reading as the agent.

Why

Buzz agents are AI assistants, such as Claude or Codex, that a person sets up in the Buzz desktop app. They answer when someone mentions them in a channel, and they can also watch for events and run on a timer. Today an agent runs only while its owner's desktop app is open, because the code that runs agents lives inside the app.

The goal of this stack is a small command-line program that runs an agent with the app closed. It must use the same code as the app, so the agent behaves the same wherever it runs. The app keeps working exactly as it does today.

Stack

Review in order. Each PR keeps the app working.

1. refactor(agents): separate the agent runner and its reads from the desktop app #961: move the code that decides when an agent runs into its own module.
2. refactor(agents): let Claude and Codex read the community through a host interface #962 (this PR): let the Claude and Codex agent code read conversations without depending on the app.
3. feat(agent-host): run a saved agent without the desktop app #967: add buzz-agent-host, the program that runs an agent with the app closed.

Details

• src/features/agents/reads.ts: the AgentReads interface (channel facts, conversation reads, profiles, names, memories, and which community the agent is in), plus ownerReads, the app's implementation. ownerReads is the existing code, moved.
• Before, these runtimes got the owner's whole session object from the plugin API (ctx.agents.relay(pubkey)). That object exists only inside the app. The interface lists only the reads an agent needs.
• src/bundled/claude-code/run.ts and src/bundled/codex/run.ts: the parts of each agent type that run an agent (model list, run, hand-over deadline), without its settings screens. A program with no user interface can load them. The app registers them with their screens as before.
• The memory read now accepts a cancel signal. Claude keeps its existing 5-second limit.
• fromOwner, the check that only the owner or the owner's agents can give an agent instructions, moves next to the signature check it uses. The agents service still exports it.
• The Claude and Codex runtime tests change only how they build their fake session: they wrap it in ownerReads.

[loganj]

🤖 Combined into #961 at Logan's request: #961 now contains these two commits unchanged (agent-host-runner fast-forwarded to d6928af). #967 is retargeted onto #961.