EBP-3105: Add Python API routing and the guaranteed pub/sub Quickstart

[aelsammak]

What is the purpose of this change?

First slice of Solace Python API support in the solace-application-development skill (the Python mirror of the JCSMP routing work). Python requests now route to a Python entry file, and the skill can design any Python leaf and generate the Quickstart guaranteed pub/sub project from the EBP-3103 samples.

How is this accomplished?

1. SKILL.md description adds the Python signals (solace-pubsubplus, MessagingService, PersistentMessageReceiver, "Solace Python API", building a Solace app in Python) and drops Python from the exclusions; JMS, the Solace Messaging API for Java, Go, .NET, and JavaScript stay excluded. The Messaging API for Java shares MessagingService and PersistentMessageReceiver with Python, so the routing text also stops on it explicitly. The description is 1014 of the 1024 characters the spec allows.
2. API Selection gets a Python row, and the JCSMP row now requires Java or a JCSMP name. Unclear but Java routes to JCSMP, unclear but Python routes to Python, and a request with no language asks "JCSMP (Java) or Python?" first. The one exception is a saved solace-design.md the developer asks to build from: its title names the API.
3. Invariant 3 names the registry per API (Maven metadata for JCSMP, PyPI info.version for Python). Invariant 5 refers to the API's own bundled verify script, and an API without one (Python, until EBP-3107) ends in the compile-only fallback every time. python.md states this in its own section.
4. New references/python.md (mode detection with the three gates, the PyPI lookup command, canonical .md links, live exceptions: the Sphinx reference, PYTHON_API_RN, PyPI) and python/prerequisites.md (broker options, supported environments, no multiprocessing).
5. python/design-mode.md: the same tree with five leaves. A guaranteed request-reply answer quotes the Request-Reply page and offers Request-Reply (Direct) or a Guaranteed Pub/Sub leaf instead.
6. python/implement-mode.md and python/implement-guaranteed-pubsub.md: the door question, then the Quickstart guaranteed pub/sub path. Generated project shape: .venv, requirements.txt pinned to the version PyPI reports at generation time (or the developer's version when PyPI is unreachable, never unpinned), gitignored config.json (keys are the Python API property names), fixed script names guaranteed_publisher.py / guaranteed_subscriber.py / solace_connection_config.py, and the same four VERIFY: markers as JCSMP.
7. Verification (Step 5): py_compile, an import smoke, and three shell checks (header on every .py file, checklist present, requirements.txt pin matches PyPI), then the handed-back run commands. A manual run on request follows the JCSMP exit 2 rule: a broker, credential, or queue-bind failure is reported and the code is not changed.
8. Interim checklist (Step 6) follows the JCSMP master: one canonical doc link per Delivered and Your-responsibility item, command line credentials and stronger auth under Your responsibility, and the Grounding-docs and conformance items that Step 5 checks.
9. Concurrency guidance: receive_async() is not asyncio compatible and calls the handler on a new thread per message, and any routine can ack before the receiver terminates (both from Consuming Persistent Messages); no multiprocessing (only the PyPI page states it).
10. Interim pieces that later stories replace: the direct leaves and the Solace Suggested and Custom doors stop with "not yet available" (EBP-3106), and Step 6 carries the interim checklist until the master template lands (EBP-3107).
11. Trigger evals: the two Python cases flip to positives (the guaranteed pub/sub one is must_pass), plus Go, JavaScript, Python asyncio without Solace, confluent-kafka, and Solace Messaging API for Java near-miss negatives.

Anything reviews should focus on/be aware of?

• Local eval results:
  • Trigger evals, 3 runs per case, on the final commit: claude-sonnet-5 62/62 passed (100%), claude-opus-5-5 62/62 passed (100%), no must_pass failures. Haiku not run locally yet.
  • Output evals (JCSMP regression), claude-sonnet-5, 1 run, on the first commit (before the review fixes): 9/11 passed, live verify skipped (no broker configured). appdev-code-before-confirm-negative (must_pass) failed once: the model treated "skip any design discussion" as a full design and picked the Quickstart door itself. A 3-run majority of that case PASSED on both a clean origin/dev checkout and this branch, so I read it as model variance, not a regression. appdev-design-summary-positive failed on tool_use Write absent because Claude Code auto-memory wrote files under memory/; the skill wrote no project file. That grader needs an auto-memory exclusion (eval corpus change, not in this PR). The review fixes touch only Python files, the routing text, and the JCSMP prerequisites sentence; output evals were not re-run after them.
  • Python flow (no Python output corpus yet, that is EBP-3108): two temporary cases ran on Sonnet from a scratch copy on the first commit. The Quickstart guaranteed pub/sub flow passed every grader (design confirm, door question, PyPI resolution, header on every file, all four markers, no reconnect block, py_compile, import smoke, Python doc fetch). The new Step 5 shell checks were tested on a scratch project: silent on a correct project, and they reported a removed header, a missing checklist, and a stale pin.
• No live round trip against a broker yet; the run is handed back by design until EBP-3107.
• jcsmp/prerequisites.md changes one sentence: the Try Broker page covers local and cloud setup only, and does not mention a container, a VM, or an Appliance. The Python file copied the same sentence.
• For EBP-3108: the output runner skips only target/ when it looks for generated files, so Python graders must also skip .venv/ or they match the API's own sources.
• Fan-out is concrete for Python (one subscriber script per consuming service, guaranteed_subscriber_<service>.py, wired through the heads-up, run commands, and checklist); the JCSMP text leaves this open. Is that the shape we want?
• No version bump (feature PR).

[mtite-sol]

Changes LGTM!