Add batch mode support for Folddisco queries

[igmorv-genesis]

Summary

Add support for querying multiple protein structures with multiple motifs in a single Folddisco job request, using the folddisco query -q <batch_file> CLI interface.

API changes

• Accept queries[] and motifs[] array parameters for batch submissions via both multipart/form-data and URL-encoded requests
• Each motifs[] entry may contain multiple motifs separated by ;, allowing a single structure to be searched with several motif specifications without re-uploading
• Add configurable top parameter to control the number of results per query (default: 1000)
• Single-query mode (q + motif parameters) remains fully backward-compatible

Backend changes

• folddiscojob.go: Add Motifs [][]string and queries []string fields for batch state. Add WriteBatchFiles() to generate per-query structure files and a 3-column tab-separated batch file (structure path, motif, output path). Extract validateFolddiscoDatabases() helper. Include Top and batch fields in job hash for correct caching.
• jobsystem.go: Dispatch to WriteBatchFiles() for batch jobs in WriteSupportFiles.
• server.go: Parse queries[]/motifs[] arrays in the ticket handler, split ;-separated motifs, and route to NewFoldDiscoBatchJobRequest or NewFoldDiscoJobRequest.
• worker.go: For batch jobs, generate a per-database 3-column batch file with output paths in column 3 so each query writes to its own file (avoiding interleaved multi-threaded output). Run a single folddisco query -q <batch_file> invocation with full threading. Concatenate per-query result files into the final alignment output. Extract ismmCIFFirstLine(), readBatchLines(), and concatFiles() helpers.

Batch file format

The generated batch file follows the folddisco query -q specification:

Column	Description
1	Path to the query structure (PDB/mmCIF)
2	Comma-separated list of motif residues
3	Path to the output file (avoids stdout interleaving)

Example usage

# Batch: two structures with different motifs, top 10 results each
curl -X POST http://host/api/ticket/folddisco \
  -F "queries[]=@structure1.pdb" \
  -F "queries[]=@structure2.cif" \
  -F "motifs[]=A10,A25,A32" \
  -F "motifs[]=A5,A15" \
  -F "database[]=h_sapiens_folddisco" \
  -F "top=10"

# Single query (unchanged)
curl -X POST http://host/api/ticket/folddisco \
  -F "q=@query.pdb" \
  -F "motif=A10,A25,A32" \
  -F "database[]=h_sapiens_folddisco"