Don't consider hosts on "bad" QUIC ports usable

[chris124567]

Close #941

[claude]

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[Copilot]

Pull request overview

This PR ensures hosts advertising QUIC endpoints on browser-blocked ports are treated as unreachable/unhealthy for QUIC/WebTransport use cases (closes #941), by filtering such addresses at ingestion time and cleaning up existing stored addresses.

Changes:

• Add a browser-blocked QUIC port set and reject QUIC announcements on those ports during host announcement validation.
• Add a Postgres migration to delete existing QUIC host_addresses entries on blocked ports.
• Extend host manager tests to cover blocked-port QUIC announcements (drop QUIC-only host; keep siamux when mixed).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
persist/postgres/migrations.go	Adds a migration deleting stored QUIC addresses that use browser-blocked ports.
hosts/manager.go	Introduces badQUICPorts and updates validateAddress to reject QUIC addresses on blocked ports.
hosts/manager_test.go	Adds test cases verifying blocked-port QUIC announcements are ignored/dropped as intended.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated no new comments.

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