[Feature]: Option to open terminal links directly on plain click

### Problem or use case

Plain-clicking a link in the terminal opens the link action popover (#13414). To open a link directly, I have to hold ⌘ (Ctrl on other platforms).

I almost always pick the same destination (Orca Browser, with "Link Routing" turned on), so every link costs either an extra click in the popover or a ⌘ press.

Turning off "Show link actions" does not help: a plain click then does nothing, and ⌘-click is required.

Environment: Orca 1.4.200, macOS.

### Proposed solution

Add a setting for what a plain click on a terminal link does, for example "Plain click on a link":

- Show link actions (current default)
- Open directly (same routing as ⌘-click, so it honors "Link Routing")
- Do nothing (require ⌘-click)

When "Open directly" is selected, ⌘-click could show the link action popover instead, so the other actions (Copy link, System Browser) stay reachable. Shift variants keep their alternate routing.

The selection, drag, and TUI mouse protections added in #13414 should still apply, so drag-to-select keeps working.

### Alternatives or additional context

- Current workaround: ⌘-click, or plain click and then choose "Orca Browser" in the popover.
- Remapping click to ⌘-click with a key remapper (e.g. Karabiner-Elements) is not viable, because it applies to the whole app. For example, ⌘-click in the built-in browser opens a new tab.
- Related:
- #9279 (item 2, "Simpler primary activation ... plain click")
- #13414 (added the link action popover on plain click)
- #14814 (modifier swap for file links; this request is about http(s) links and the plain click itself)

Start by tracing the terminal link click handling and the link-action popover behavior added in #13414. Check how plain clicks, ⌘-clicks, selection, dragging, and TUI mouse handling interact. Done means a setting supports the three proposed plain-click behaviors while preserving link routing, alternate shift actions, and access to other link actions.

Written by the indexing model from the issue text.