refactor!: Migrate Force Press events to new API

[luanpotter]

Description

Migrate Force Press events to new API, removing the old one.
This is basically a 1:1 migration to the new system.

NOTE: this is a super edge-case API that we could also just consider removing it - apparently apple while has not officially killed it has effectively done so, and never been really a thing on Android. However, Flutter still supports it first class (and not deprecated), so I just migrated as is as the effort is low and won't impact our migration. We can still consider dropping later on as part of v2.

Checklist

• I have followed the Contributor Guide when preparing my PR.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples or docs.

Breaking Change?

• Yes, this PR is a breaking change.
• No, this PR is not a breaking change.

[Copilot]

Pull request overview

This PR migrates Force Press input handling from the deprecated game-level detector API (ForcePressDetector / ForcePressInfo) to the component-based callbacks/dispatcher event system, aligning it with the rest of Flame’s input architecture and documenting the breaking change.

Changes:

• Removed ForcePressDetector and ForcePressInfo (and their GameWidget recognizer wiring) from the old gestures detector system.
• Added ForcePressCallbacks, ForcePressDispatcher, and ForcePressEvent to route force press gestures through the component tree.
• Replaced/added tests and updated migration + input documentation for the new Force Press API.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/flame/test/gestures/detectors_test.dart	Removes legacy ForcePressDetector tests tied to the old API.
packages/flame/test/events/component_mixins/force_press_callbacks_test.dart	Adds new tests for component-based force press dispatch, propagation, and lifecycle.
packages/flame/lib/src/gestures/events.dart	Removes legacy ForcePressInfo event wrapper.
packages/flame/lib/src/gestures/detectors.dart	Removes legacy ForcePressDetector mixin and handlers.
packages/flame/lib/src/game/game_widget/gesture_detector_builder.dart	Removes old Force Press recognizer registration for ForcePressDetector.
packages/flame/lib/src/game/flame_game.dart	Updates hit-testing detection to include ForcePressCallbacks components.
packages/flame/lib/src/events/messages/force_press_event.dart	Introduces ForcePressEvent as the new force press position event.
packages/flame/lib/src/events/dispatchers/force_press_dispatcher.dart	Introduces dispatcher that registers the recognizer and routes events to callbacks.
packages/flame/lib/src/events/callbacks/force_press_callbacks.dart	Introduces ForcePressCallbacks mixin and isForcePressed state.
packages/flame/lib/events.dart	Exports the new Force Press callbacks, dispatcher, and event; removes legacy exports.
packages/flame_test/lib/src/mock_force_press_events.dart	Adds a test helper for constructing ForcePressEvent.
packages/flame_test/lib/flame_test.dart	Re-exports the new force press mock helper.
doc/flame/migration.md	Documents the breaking migration from detector/info to callbacks/event.
doc/flame/inputs/tap_events.md	Documents ForcePressCallbacks usage and behavior.
doc/flame/inputs/gesture_input.md	Removes ForcePressDetector from the detector list.

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[luanpotter]

this is wrong, it does work at game level, because componentsAtPoint includes the game itself
that being said there are other new detectors missing here, which is indeed a bug, and this is not tested, but it is not tested for other detectors either
so I will followup with a broad approach here, but not part of this PR

[spydon]

I think we should just drop this instead

[luanpotter]

@spydon I was over the fence, but that settles it then, let me just drop

[adario]

(Apologies to intervene like this: on iOS, nowadays the UITouch.force property is used only on iPad by some drawing apps, since the Apple Pencil supports it... honestly, I've not seen the property used on iPhone for several years now.)

[luanpotter]

That's great context @adario , thanks for providing!

I opened an alternative to just remove it, it can still be easily used by wrapping the game with your own flutter gesture detector, so I think this is totally acceptable

#3989