swarm-logs: authenticate as the agent with its own queue secret

swarm-logs reads `swarm/agents/<agent>/queue` from the swarm secret
store with the agent's own store certificate (the read hive-agent makes
for its queue connection) and presents it as
`Bearer swarm-agent.<agent>.<secret>`, which the gateway's
swarm-logs-auth checks. On a 401 it reads the secret again and retries
once, so a secret re-minted between the read and the check does not
fail the query.

The OIDC mint against the hive's shared `hive-<h>-agent` client is gone
from swarm-logs, along with the unused `HIVE_AGENT_OIDC_CA_FILE` anchor.
logs.nix now gates on the store address instead of the queue's token
endpoint and wraps the binary with the paths queue-identity.nix gives
the harness; the host forwards the query URL wherever it forwards a
store identity.

The shared client is still delivered into containers; removing that is

Part of #4459.

swarm-logs/src/main.rs

@@ -85,6 +85,7 @@ fn main() -> Result<()> {
             // keep working on a machine that has no log store wired up at
             // all — `markdown-docs` in particular runs in a nix check, where
             // no credential exists and none should.
+            swarm_queue_client::install_crypto_provider();
             let cfg = auth::Config::from_env()?;
             let stdout = std::io::stdout();
             query::run(&cfg, &logsql, limit, format, &mut stdout.lock())