ui: stack manager

[greatgitsby]

move bespoke panel switching and bespoke modal handling into a single stack interface

likely going to break out changes from this, there are a few fundamental changes in this PR:

• set_modal_overlay no longer needed, use stack
• couple bugs found in keyboard renderer
• "modal" operated differently than normal "widget" as it had a return code and handled it uniquely. want to make this a general feature of Widget.
• i hate callback invoking pop, it should be simpler than this (dismiss should auto-handle pop if no action was taken)

[github-actions]

raylib UI Preview

homescreen : $${\color{red}\text{DIFFERENT}}$$

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homescreen_update_available : $${\color{red}\text{DIFFERENT}}$$

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keyboard : $${\color{red}\text{DIFFERENT}}$$

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onroad_full_alert : $${\color{red}\text{DIFFERENT}}$$

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onroad_full_alert_long_text : $${\color{red}\text{DIFFERENT}}$$

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onroad_full_alert_multiline : $${\color{red}\text{DIFFERENT}}$$

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settings_network : $${\color{red}\text{DIFFERENT}}$$

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settings_network_advanced : $${\color{red}\text{DIFFERENT}}$$

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settings_software_branch_switcher : $${\color{red}\text{DIFFERENT}}$$

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settings_software_release_notes : $${\color{red}\text{DIFFERENT}}$$

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All Screenshots

[sshane]

BTW a requirement for this kind of PR should be: easy to render the previous widget behind if swiping away

[github-actions]

This PR has had no activity for 24 days. It will be automatically closed in 7 days if there is no activity.

[github-actions]

This PR has been automatically closed due to inactivity. Feel free to re-open once activity resumes.

[sshane]

won't this re-create the layouts each time?

[sshane]

still need these show_events I think

[sshane]

Working on this in #37094

[greatgitsby]

superseded by #37094