Open a terminal link on a plain click

[bharathm03]

Follow-up to #14. The links still did not work where it mattered.

Why

Measured on Claude Code's own PTY, not inferred:

MOUSE modes enabled: 1000, 1002, 1003, 1006   <- all-motion SGR, in its first frame
OSC 8 URIs seen: 2  ["https://claude.ai/code/session_...", ...]

A full-screen agent takes the mouse before it prints anything, so _handleTapUp hit the mouse-capture guard and returned before hyperlink resolution on every click -- while the render path kept painting the cell blue and underlined, because hasHyperlink paints unconditionally. Shift+click reached the link; nothing on screen said the chord existed. That is the original bug, still standing in the one case the OSC 8 work was written for.

#14 had already decided a bare finger tap should open an explicit OSC 8 link even when the program holds the mouse -- OSC 8 is the program declaring these cells are a link, which outranks its claim on the pointer. That argument never depended on the pointer being a finger.

What is in here

Pin bump to antgrid-ai/dart_terminal#6 (ce7f469 -> f8e2e82), which:

• opens an explicit OSC 8 link on a plain primary click, withholding the whole press-motion-release span so the agent is never handed half a click
• leaves bare-URL matches, cells outside the link, and right/middle click with the agent
• keeps Shift meaning what it meant, now as the way to reach a bare-URL match
• makes hover mark only what a click will actually open

Six tests there, each negative-checked against a reverted terminal_view.dart.

A wrong claim this turned up

_revealsDestinationOnHover skipped the confirm sheet on desktop because "Desktop does, through the terminal's hover affordance, so a click there is already an informed one."

That is false and always was. _hoveredHyperlink drives one thing -- SystemMouseCursors.click -- and neither the view nor this app ever paints the URI. So the desktop path was skipping the spoof check on a premise that does not hold, and this PR makes that path reachable in one plain click.

The gating is still right, for a different reason: desktop hands the URI to a browser whose address bar reads it back, which is the disclosure every terminal leans on. Mobile has no such guarantee -- an https: host holding a verified App Link opens that app instead of any browser, so the destination can be acted on without ever being shown. Renamed to _browserRevealsDestination and documented as that.

The real fix for desktop is a hover preview of the destination, which needs an onHyperlinkHover callback the fork does not expose yet. Not in scope here; flagged rather than quietly left as-is.

Gates

App suite +2617 ~2, all pass. flutter analyze clean. check:font-tokens OK. Fork: +208 -28, the 28 pre-existing on master.

Not verified in the running app

flutter_driver has no tap-at-coordinate command, so a terminal cell is not reachable from the harness. The evidence is the PTY measurement plus the widget tests.