Merge develop into main (#348)

## App state

Improved app state management in `LoaderService` and `GuiService`:

- Re-ordered some of the state transitions
- Hardened `GuiService` for repeated events (that might trigger a re-render of an app that's already rendered)
- Validate state transitions in `LoaderService` and crash if an app transitions from the wrong state to the next one.

## LoaderService

- Removed `tt::loader::` functions and expose `LoaderService` interface publicly.
- Implement `stopAll()` and `stopAll(id)` which stops all instances of an app, including any apps that were launched by it.
- Rename `stop()` functions to `stopTop()`
- Created `stopTop(id)` which only stops the top-most app when the app id matches.
- Moved `loader::LoaderEvent` to `loader::LoaderService::Event`
- Changed app instance `std::stack` to `std::vector`

## Improvements

- `ElfApp`: error 22 now shows a hint that `main()` might be missing
- Starting, installing and uninstalling apps now stops any running app (and its children) on the stack

## Bugfixes

- `HttpdReq` out of memory issue now shows an error message and doesn't crash anymore (this would happen on devices without PSRAM with WiFi active, when an app was installed)
- `GuiService::hideApp()` lock should not wait for timeout and now waits indefinitely
- `Buildscript/release-sdk-current.sh` deletes the previous local release before building a new one

## Code correctness

- App classes were made `final`
- Apps that had a `void start()` now have a `LaunchId start()`
- `tt::app::State`: renamed `Started` to `Created` and `Stopped` to `Destroyed` to properly reflect earlier name changes

Documentation/ideas.md

@@ -2,14 +2,12 @@
 
 ## Higher Priority
 
-- Show a warning in the web installer when flashing CYD 28R board regarding v1/v2/v3
-- External app loading: Check the version of Tactility and check ESP target hardware to check for compatibility.
+- External app loading: Check the version of Tactility and check ESP target hardware to check for compatibility
+  Check during installation process, but also when starting (SD card might have old app install from before Tactility OS update)
 - Make a URL handler. Use it for handling local files. Match file types with apps.
   Create some kind of "intent" handler like on Android.
   The intent can have an action (e.g. view), a URL and an optional bundle.
   The manifest can provide the intent handler
-- CrowPanel Basic 3.5": check why GraphicsDemo fails
-- CrowPanel Basic 3.5": check why System Info doesn't show storage info
 - When an SD card is detected, check if it has been initialized and assigned as data partition.
   If the user choses to select it, then copy files from /data over to it.
   Write the user choice to a file on the card.
@@ -17,14 +15,6 @@
   The latter is used for auto-selecting it as data partition.
 - Support direct installation of an `.app` file with `tactility.py install helloworld.app <ip>`
 - Support `tactility.py target <ip>` to remember the device IP address.
-- External app error code 22 should warn that the user might've forgotten a `main()` entry point
-- Bug: `Buildscript/release-sdk-current.sh` should delete the currently released SDK. It should probably also output it with versioning and target platform naming so it can be referred to as if it is a real release.
-- Tactility docs: external app dev guide should explain [debugging](https://docs.zephyrproject.org/latest/services/llext/debug.html)
-- elf_loader changes/suggestions:
-    - Make entry-point optional (so we can build libraries, or have the `manifest` as a global symbol)
-    - Implement support for alternative symbol lists. e.g. a function pointer that resolves a single symbol.
-- Implement the entire list of [soft-float library functions](https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html) to `tt_init.cpp`
-- `tactility.py` should stop running applications when it is: uninstalling, installing, or running an application that is already running.
 
 ## Medium Priority
 
@@ -40,9 +30,11 @@
 - Bug: Crash handling app cannot be exited with an EncoderDevice. (current work-around is to manually reset the device)
 - I2C app should show error when I2C port is disabled when the scan button was manually pressed
 - TactilitySDK: Support automatic scanning of header files so that we can generate the `tt_init.cpp` symbols list.
+- elf_loader: split up symbol lists further (after radio support is implemented)
 
 ## Lower Priority
 
+- elf_loader: make main() entry-point optional (so we can build libraries, or have the `manifest` as a global symbol)
 - Implement system suspend that turns off the screen
 - The boot button on some devices can be used as GPIO_NUM_0 at runtime
 - Localize all apps