test(integration-tests): add Ebola Sudan submission edge-case tests

[corneliusroemer]

Add an exploratory Playwright spec that submits + releases Ebola Sudan
sequences with "interesting" characters in metadata and verifies they are
findable in search and on the /seq detail page.

Covers, against main.loculus.org:

• submissionId with emoji, combining diacritics, RTL/zero-width/BOM,
  HTML/script-like, path-traversal-like, quotes/template-literal, very
  long (500 chars), null byte, and raw invalid UTF-8 bytes
• free-text fields with the above plus control characters (LF, CRLF, tab,
  VT/FF/ESC/BEL), expressed via RFC4180 TSV quoting
• post-release verification: sequence appears in search and /seq/
  detail page renders

Findings: all accepted/released/searchable except 500-char and null-byte
submissionId, which are rejected at submission.

Adds raw-byte upload helpers (uploadRawMetadataFile / uploadRawSequenceFile)
to BulkSubmissionPage for byte-exact TSV/FASTA.

Co-Authored-By: Claude Opus 4.8 noreply@anthropic.com

resolves #

Screenshot

PR Checklist

• All necessary documentation has been adapted.
• The implemented feature is covered by appropriate, automated tests.
• Any manual testing that has been done is documented (i.e. what exactly was tested?)

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[claude]

This PR may be related to: #6795 (Null byte in submission id causes 504 at database insertion - not caught by backend before). The PR's edge-case tests explicitly cover null-byte submissionIds and note they are rejected at submission.