afx whoami + ship /arch-init command in codev (multi-architect identity)

[waleedkadous]

Summary

Two related improvements to support multi-architect workspaces:

1. New afx whoami command — reports, from Tower/global.db's perspective, who the current terminal's agent is:

   workspace: codev
   type: architect
   name: main
   

   For builders:

   workspace: codev
   type: builder
   name: builder-spir-984
   architect: main        # spawnedByArchitect, when known
   

   Should support --json. When identity cannot be determined (plain shell, unregistered terminal), say so clearly — fail loud, no guessing (see afx send: detectCurrentBuilderId silently falls back to bare worktree name on state.db read failure → builder messages misroute to main #1094 for why silent identity fallbacks are dangerous).

2. Move the /architect slash command into codev itself, renamed /arch-init — today it lives only in the architect's personal ~/.claude/commands/architect.md. It should ship with codev (skeleton → all adopting projects) so any architect terminal in any codev workspace can run /arch-init to adopt its identity and recover state from codev/state/<name>.md.

   /arch-init must use afx whoami for identity resolution — replacing the current fragile ps -p $PPID process-ancestry matching against afx status output. If whoami resolves the identity, use it; an explicit [name] argument still overrides; if neither, stop and ask the human (never guess).

Existing plumbing to build on

• Tower already sets CODEV_ARCHITECT_NAME in architect PTY env (packages/codev/src/agent-farm/servers/tower-terminals.ts:654 and :897) — the natural signal for architect identity.
• detectCurrentBuilderId() in packages/codev/src/agent-farm/commands/send.ts:111 resolves builder identity from cwd + global.db, scoped by workspace_path, failing loud (BuilderIdResolutionError) per afx send: detectCurrentBuilderId silently falls back to bare worktree name on state.db read failure → builder messages misroute to main #1094. whoami should reuse/share this, not duplicate it.
• Architect rows (name, pid, terminal id) live in the architect table in ~/.agent-farm/global.db (Consolidate state.db tables into global.db (single user-global database) to eliminate the cwd-dependent fragmentation that causes "missing architect state after restart" #1118).

Design notes / constraints

• Identity precedence for whoami: builder-worktree cwd match → CODEV_ARCHITECT_NAME env → unknown (exit non-zero with a clear message). Do not fall back to "main" implicitly.
• /arch-init content should be generalized (the current ~/.claude/commands/architect.md is Shannon-workspace-flavored) — workspace-agnostic wording, same guardrails (never auto-approve gates, only touch your own builders, never cd into worktrees, stay on default branch at root).
• Ship /arch-init via codev-skeleton/ so codev init / codev update installs it; mirror in our own instance. Remember the two-tree rule: change BOTH codev/ and codev-skeleton/ where applicable.
• whoami must work from both the main workspace root (architect) and inside a .builders/<id>/ worktree (builder).

Acceptance criteria

• afx whoami from an architect terminal prints workspace/type/name matching Tower's records.
• afx whoami from a builder worktree prints the canonical builder id (+ spawning architect when recorded).
• afx whoami in an unrecognized context exits non-zero with a helpful message.
• /arch-init [name] resolves identity via afx whoami (arg overrides), reads codev/state/<name>.md, and reports the resume summary.
• /arch-init ships in the skeleton and resolves in fresh installs.