hive-claude 0.1.4: the idle watchdog stops claude with SIGINT

hive-claude 0.1.4 (hive-claude #28) sends the idle watchdog's signal as
SIGINT to claude's process group instead of SIGKILL. It then waits for
claude to exit, with no SIGKILL fallback. claude stops the commands its
Bash tool started when it shuts down on SIGINT, and a SIGKILL left them
running. This is the last SIGKILL of a claude process from #4999.

hive-agent's `idle_timeout` -> `Error::IdleTimeout` -> `TurnError::ApiStall`
path is unchanged. The difference is that the error now arrives only
once claude has exited. A claude that ignores the SIGINT keeps the turn
open until it is killed by hand or the unit stops.

The Cargo.lock change is only hive-claude's version and checksum. A plain
`cargo update -p hive-claude --precise 0.1.4` also moved seven crates'
Windows-only `windows-sys` edges from 0.61.2 to 0.52.0, unrelated to this
bump. The minimal lock passes `--locked`.

The turn-loop and web-UI docs, and hive-agent's watchdog docs and stall
note, now say SIGINT instead of "killed". That includes the ACP spots
that the previous commit's `Drop` change made stale.

docs/web-ui/agent.md

@@ -229,7 +229,7 @@ Slash commands today:
 - `/clear` — wipe the local terminal view (server history kept).
 - `/cancel` — `POST /api/cancel` → SIGINT to the turn's claude and every
   command it started (its process group), emits a Note. On an ACP agent
-  it sends the agent `session/cancel` instead, and kills it if the turn
+  it sends the agent `session/cancel` instead, and SIGINT if the turn
   hasn't ended 10s later. Also surfaces as a `■ cancel turn` button in
   the state row while state=thinking.
 - `/compact` — `POST /api/compact` → sets the deferred