fix improve Run App url matching and fix preview timeout issue

[sharon-wang]

This is a follow-up to #5336 to bring in additional fixes from the corresponding PR #5349 on main.

Related issues

• https://github.com/posit-dev/positron/issues/5197
• https://github.com/posit-dev/positron/issues/5306

Related PRs

• https://github.com/posit-dev/positron/pull/5336
• https://github.com/posit-dev/positron/pull/5349