codedb-cli: deps uses wrong JSON field + root mismatch on running daemon

[justrach]

Found by Codex review on PR #88.

Bug 1: deps command uses wrong JSON field

scripts/codedb-cli line 121 does:

_get "/explore/deps?path=$(_urlencode "$1")" | jq -r '.dependents[]'

But the server (src/server.zig) returns the list under imported_by, not dependents. With set -euo pipefail, this makes deps fail on every call.

Fix: Change .dependents[] to .imported_by[]

Bug 2: Root mismatch when daemon already running

_ensure_server returns immediately if /health succeeds, regardless of what [root] was requested. If a daemon is already running for repo A, calling codedb-cli /repo-b tree silently returns repo A's results.

Fix: Check the running daemon's root (via /status or similar) and restart if it doesn't match the requested root.

Origin

Both found by Codex automated review on #88. The core fixes in #88 (stack overflow + codesign) are unaffected — these are CLI wrapper issues only.