[FLINK-40152][connector/postgres] Make table filtering case-sensitive

[qiuyanjun888]

What is the purpose of this pull request?

Fix FLINK-40152, where the PostgreSQL CDC connector captures case-variant tables even when only one table is configured. PostgreSQL quoted identifiers are case-sensitive, but the Debezium table include predicate is case-insensitive by default.

Brief change log

• Preserve the existing Debezium table filter and additionally apply the effective table.include.list as case-sensitive full-match regular expressions.
• Reapply the case-sensitive filter after split-specific PostgreSQL connector configurations are rebuilt.
• Add unit coverage for regex matching, case-only sibling exclusion, and connector-config reconstruction.

---

Verifying this change

This change added tests and can be verified as follows:

• Added PostgresSourceConfigTest.
• Ran mvn -pl flink-cdc-connect/flink-cdc-source-connectors/flink-connector-postgres-cdc -am -Dtest=PostgresSourceConfigTest -Dsurefire.failIfNoSpecifiedTests=false test.
• Result: 2 tests passed; Spotless, Checkstyle, production compilation, and test compilation passed.

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

---

Was generative AI tooling used to co-author this PR?

• Yes — Hermes Agent with OpenAI Codex (GPT-5.6)

Generated-by: Hermes Agent with OpenAI Codex (GPT-5.6)