PeerDB UI: Rename hard delete, hide soft delete for CH mirrors

[Amogh-Bharadwaj]

Currently there is some confusion in the user community around these two toggles and their behaviour for CH mirrors.
The _peerdb_is_deleted column is currently mandatory for ClickHouse. Therefore the soft delete switch is irrelevant as well as the "Disable all PeerDB Columns" switch.
Hard delete is a misleading setting name, changes it to be more specific

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
2162	1	2161	162

View the top 1 failed test(s) by shortest run time

github.com/PeerDB-io/peerdb/flow/connectors/mysql::TestMySQLSSHResetPeer

Stack Traces | 17s run time

=== RUN   TestMySQLSSHResetPeer
2026/03/30 13:44:46 INFO Setting up SSH connection x-peerdb-additional-metadata={Operation:FLOW_OPERATION_UNKNOWN} Server=localhost:42003
    ssh_keepalive_test.go:83: Adding reset_peer toxic - should cause immediate connection failure
2026/03/30 13:45:01 ERROR Keepalive request failed, marking tunnel as bad x-peerdb-additional-metadata={Operation:FLOW_OPERATION_UNKNOWN} error=EOF
2026/03/30 13:45:01 INFO SSH keepalive failed, closing connection x-peerdb-additional-metadata={Operation:FLOW_OPERATION_UNKNOWN}
    ssh_keepalive_test.go:83: Query should have failed quickly due to connection reset, not timeout
2026/03/30 13:45:03 INFO Closing MySQL connector x-peerdb-additional-metadata={Operation:FLOW_OPERATION_UNKNOWN}
2026/03/30 13:45:03 ERROR [mysql] failed to close SSH tunnel x-peerdb-additional-metadata={Operation:FLOW_OPERATION_UNKNOWN} error="close tcp [::1]:46624->[::1]:42003: use of closed network connection"
--- FAIL: TestMySQLSSHResetPeer (17.03s)

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[github-actions]

🔄 Flaky Test Detected

Analysis: Docker Hub returned a 500 Internal Server Error when pulling mysql:5.7, causing an infrastructure setup failure unrelated to any code change.
Confidence: 0.97

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[github-actions]

🔄 Flaky Test Detected

Analysis: TestMySQLSSHResetPeer is a timing-sensitive test that injects a network reset via toxiproxy and expects the query to fail quickly, but it non-deterministically times out instead — a race between connection teardown propagation and the query deadline.
Confidence: 0.88

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