Add Publisher-based publishing workflow

[mconflitti-pbc]

Summary

• add a first-class posit connect publish command backed by rsconnect-python's Publisher API
• automatically open the setup wizard when an interactive user publishes a fresh project
• provide posit connect publish --init for configuring a project without deploying it
• add a Questionary-powered setup experience with Connect styling, project discovery, dependency configuration, and file inclusion choices
• preserve Publisher configuration fields and reuse saved server/content deployment records on later publishes
• raise the Python floor to 3.9 and pin the rsconnect-python PR 830 commit until its Publisher API is released
• add a FastAPI end-to-end suite using posit-dev/with-connect, including setup, first publish, authenticated response verification, source update, and republish reuse

Verification

• 85 passed, 1 skipped on Python 3.9 and Python 3.13 without live Connect credentials
• Ruff formatting and lint checks pass
• local just integration passes against Posit Connect 2026.08.0 using Docker and the repository test license
• wheel and sdist build successfully

[mconflitti-pbc]

Screen.Recording.2026-08-13.at.10.42.06.AM.mov