fix: headless init does not stamp project time_initialized so memory stays inert

[LeXwDeX]

Why

Running /init through headless entrypoints (opencode run, opencode serve + HTTP API) writes AGENTS.md but never stamps project.time_initialized in the DB, so MEMORY stays fail-closed inert forever with no hint. Interactive TUI stamps correctly. Verified on released v1.0.29 and v1.0.28 binaries (not a 1.0.29 regression; long-standing headless gap).

Repro (verified on darwin-arm64 release binaries)

1. Fresh git repo, then: opencode run "/init" twice → AGENTS.md written, but sqlite3 ~/.local/share/opencode/opencode.db "SELECT time_initialized FROM project WHERE worktree LIKE '%<repo>%''" stays empty
2. opencode serve + POST /session/:id/message with /init → same result
3. Interactive TUI on same repo → stamp lands

Suspected mechanism

packages/opencode/src/project/project.ts (~L418-428) initState listens for Command.Event.Executed and matches event.location?.directory === ctx.directory. The EventV2 bridge (src/event-v2-bridge.ts) injects location from InstanceRef; when headless runs publish without a location (InstanceRef absent or a different fiber context), the listener silently drops the event.

Evidence

• DB row exists with NULL stamp after headless /init (both run and serve paths)
• git log -S 'Command.Default.INIT' shows the listener predates 1.0.29
• v1.0.28 binary reproduces identically

Acceptance

• opencode run "/init" on a fresh repo stamps time_initialized
• serve + HTTP API /init stamps as well
• Regression test covering the headless command-executed → stamp path
• TUI path keeps working (no regression)