Add configurable MCP transport CLI (stdio/sse/streamable-http) for network deployments

[Copilot]

paper_search_mcp.server:main() was hardcoded to transport="stdio", which blocked direct use in containerized and remote MCP deployments. This PR adds an additive CLI transport surface while preserving existing subprocess behavior by default.

• CLI transport and network options

  • Added --transport {stdio,sse,streamable-http} (default: stdio)
  • Added --host, --port, and --path flags to support networked serving modes
  • Kept default behavior unchanged for existing stdio consumers

• Transport-specific runtime wiring

  • sse / streamable-http: apply host and port
  • streamable-http: apply path (streamable_http_path)
  • stdio: ignore network-only options

• Input validation

  • Added strict port validation (1..65535) with clear argparse error messages for invalid/non-integer input

• Dependency floor update

  • Bumped mcp[cli] minimum version from >=1.6.0 to >=1.8.0 to align with streamable-http availability

• Docs and focused coverage

  • Updated README with example invocations for sse and streamable-http
  • Added tests/test_server_main.py to cover defaults, transport option application, and invalid port cases

# default (unchanged)
paper-search-mcp

# network transports
paper-search-mcp --transport sse --host 0.0.0.0 --port 8000
paper-search-mcp --transport streamable-http --host 0.0.0.0 --port 8000 --path /mcp

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• api.archives-ouvertes.fr
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• api.base-search.net
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• api.biorxiv.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• api.crossref.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• api.medrxiv.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• api.openaire.eu
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• api.semanticscholar.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• citeseerx.ist.psu.edu
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• dblp.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• doaj.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• eprint.iacr.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• export.arxiv.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• scholar.google.com
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• sci-hub.se
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)
• zenodo.org
  • Triggering command: /usr/bin/python python -m unittest discover -s tests -p test_*.py (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)