Keep hostnames intact when the JDBC worker redacts

[openai0229]

What

The JDBC worker redacts the username and password itself (JdbcWorker.java:122) with a plain String.replace, duplicating the CLI-side logic that #17 fixed. Because the worker redacts first, the released 0.1.7 still shows the original symptom for Oracle: the driver's help URL arrives as https://docs.[redacted].com/error-help/db/ora-17002/ whenever the password happens to be oracle.

The worker now uses the same standalone rule as the CLI: a secret is replaced only when the characters around it are neither alphanumeric nor a dot.

Verification

Same Oracle datasource and default verify-full, worker rebuilt and passed through --worker-dir:

before: … https://docs.[redacted].com/error-help/db/ora-17002/ …
after:  … https://docs.oracle.com/error-help/db/ora-17002/ (the connection failed before any statement; if this database does not serve TLS, retry with --tls disable)

• No credential leaks in the message, and the connection still succeeds with --tls disable.
• mvn -B -f java/jdbc/pom.xml verify passed.
• Found while re-running the four-database black-box flow against the published 0.1.7; the release keeps the CLI-side fix from Redact credentials without mangling surrounding text #17, so only JDBC databases were affected.

Risks and limits

• A secret glued to a word or a longer hostname is no longer redacted in that position, matching the CLI behaviour from Redact credentials without mangling surrounding text #17.
• Needs a release (0.1.8) to reach users; 0.1.7 already shipped with the CLI-side fix only.