weed-vector: check master certificates against the server allowlists, read -config_dir (#12374)

* weed-vector: look for security.toml in -config_dir first

weed processes search the directory -config_dir names before ., so a
cluster keeping security.toml there left the engine in plaintext.
--config-dir (also -config_dir, WEED_VECTOR_CONFIG_DIR) does the same.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011UpvafvK8JpagF94MHWqwK

* weed-vector: dial the masters the way weed clients do

The master's certificate must chain to grpc.ca and is not checked against
the host dialed, as weed clients verify (advancedtls.CertVerification), so
masters sharing one workload certificate, or dialed by IP, register as
they do from weed. Instead, grpc.client.master_allowed_server_commonNames,
grpc.client.allowed_server_commonNames or grpc.allowed_server_commonNames
(and the wildcard domain likewise) restrict which server identities are
accepted: the common name or a DNS SAN, or an exact URI SAN, as
security.Authenticator.AuthenticateServer does. These used to be refused
at startup; --tls-server-name is gone with the host check.

The TLS runs in a connector that reads the credentials asynchronously at
every dial, so the connect timeout still covers the reads, the TCP connect
and the handshake together. An IPv6 master's brackets are stripped before
the dial.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* test/s3vectors: the hardened leg allowlists server identities for grpc.client

The gateway and the engine then accept only servers named localhost, which
exercises the engine's allowed_server_commonNames check on the master dial.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011UpvafvK8JpagF94MHWqwK

* weed-vector: parse the refresh interval with time.ParseDuration's arithmetic

The interval was summed in floating-point seconds, so 0.9ns rounded up to
1ns where Go truncates it to 0 and falls back to the 5h default, 0.3s was
off by a nanosecond, and 3000000h was accepted where Go rejects anything
past the longest time.Duration. Each part is now an integer count of
nanoseconds plus the fraction Go adds, with Go's overflow bounds, and the
value is no longer trimmed, as Go does not trim it either.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* weed-vector: test a master dial whose credential read stalls

The bounded-dial tests passed no credentials or a prebuilt endpoint, so
moving the credential read out of the connect timeout would have failed
none of them. The new test points grpc.ca at a FIFO nobody writes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* weed-vector: dial a closed port in the stalled credential read test

Against a silent listener, a dial that never read the credentials timed
out with the same message, so the test passed without the read. Nothing
listens on the port now, so only the stalled read can time out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* weed-vector: test that Security::load searches the config dir

Only candidates() was tested, so load dropping config_dir on the way
would have passed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* weed-vector: expand a leading ~ in -config_dir like weed's ResolvePath

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* weed-vector: hold the port in the stalled credential read test

A released port can be taken before the dial, and a dial that skipped the
read would then time out and pass. A listener that drops every connection
keeps the port and still fails such a dial at once.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

test/s3vectors/conftest.py

@@ -109,7 +109,10 @@ def write_tls(directory):
             "-out", "outsider.pem", "-days", "2", "-extfile", "ext.cnf")
     cert, key, ca = (f'{key} = {json.dumps(str(directory / name), ensure_ascii=False)}\n' for key, name in (("cert", "cert.pem"), ("key", "key.pem"), ("ca", "ca.pem")))
     pem = cert + key + ca
-    grpc = "".join(f"[grpc.{component}]\n{cert}{key}\n" for component in ("master", "volume", "filer", "s3", "client"))
+    grpc = "".join(f"[grpc.{component}]\n{cert}{key}\n" for component in ("master", "volume", "filer", "s3"))
+    # Clients (the gateway, the engine) accept only servers named localhost;
+    # the engine serves only clients named localhost.
+    grpc += f"[grpc.client]\n{cert}{key}allowed_server_commonNames = \"localhost\"\n"
     grpc += f"[grpc.vector]\n{cert}{key}allowed_commonNames = \"localhost\"\n"
     (directory / "security.toml").write_text(f"[https.volume]\n{pem}\n[https.client]\nenabled = true\n{pem}\n[grpc]\n{ca}\n{grpc}")