MiSTer updates and changelog

[theflynn49]

TRS-80 :

- Add the Omikron CP/M Mapper for Model-I
- Add MrUNZIP for CP/M (so Zip files hosted by MiSTer can be unzipeed directly into CP/M files)
- Add release TRS-80_20250310.rbf

[shodge]

CoCo2:

CoCo2 / Dragon Release CoCo2_20250312 - 002
1: Recursion testing spreadsheet completed.
2: Updated MiSTer template
3: Added Daily Build Number. Note sys/build_num.tcl changed to add this functionality.
Updating the template in the future will need to restore this version to prevent
the loss of this function.
4: Changed back to Cycle accurate 09
5: Fixed Timer [The FDC cartridge does not generate a FIRQ when asserted. This was fixed..]
6: Double speed poke in the SAM via SAM registers coded. Video sync at high speed fixed
7: FDC changed to use system clk and divide to 8 Mhz changed to /6. FIRQ generation
for Dragon, qualified enabled only in Dragon configurations.
8: Fixed some incorrect menu subscript duplications
9: Added Cassette Save
10: Added minor delay to 1793 interrupt to fix dragon os9 problem. Also removed HALT from
dragon FDC.
11: Nitro OS9 working on CoCo & Dragon64.
12: ROMs removed from .rbf. Instructions for the creation in the README.MD file. Code added
to show 'NO ROMS' on output video without roms being found on load of core.

[theypsilon]

Downloader:
- Version 2.0 released.
- Rewrote Downloader's core routines with a worker-based concurrency model, maximizing parallelism in this environment while improving efficiency, scalability, and extensibility for future optimizations.
- The launcher now uses the latest build of Downloader if it's present in the filesystem. The newer version of Downloader will now be installed from MiSTer Distribution database just like any other standard MiSTer file. Thanks to this, you may now avoid executing remote code altogether by taking this additional step during installation. Otherwise, remote code execution only happens once on your first run of Downloader.
- Documented Custom INI file support in README.md, in case you want to use a separate launcher and INI file to install different databases in isolation through that launcher.
- Added a docs plot script, which helps document the internal worker architecture by generating flow diagrams.
- Added a debug CLI that assists in various development and testing processes.
- Improvements and fixes in the HTTP client, which is now working more efficiently in highly concurrent scenarios and now takes care of most caching features from the HTTP/1.1 spec. Previously, in very rare cases, connections could stall, and this no longer happens.
- Fixed timeouts not being triggered in some very rare scenarios, which, together with the previous connection-stalling bug in the HTTP client, would make the Downloader hang with a continuous array of asterisks for much longer than intended.
- Fixed a bug where Storage Priority, set to external, would not detect an existing folder with content in setups with many drives connected at the same time.
- The log file downloader.log no longer stores debug information by default unless errors occur during the process. To log debug information, set verbose=true in the INI file, as described in the README.md.
- Reboot sequence takes much less time, going from over 30 seconds to around 3 seconds.
- Fixed database filtering not working properly in various uncommon scenarios.
- Fixed bug in error handling when restoring user system files during a Linux update by daph.
- Better custom download filters documentation by NFGman. Check it here.
- Made the program react much sooner to interrupt signals (Ctrl+C) when invoked in a terminal.
- Custom database headers take up a bit less space in the output.
- A large number of minor bug fixes and improvements. Check CHANGELOG.md for more details, and check this PR (warning: +300 commits) for the full details.
- Removed the `base_path` option in database-scoped settings. Files that were previously installed in different locations due to this option will be moved to the standard location. As a reminder, general `base_path` usage was deprecated in version 1.8, as multi-drive setups are now handled with the Storage Priority feature introduced in Downloader 1.5.
- Removed `downloader_threads_limit`, `downloader_timeout`, `downloader_retries`, and `update_linux` from the database-scoped options. Instead, global values (defined under `[mister]` heading) are used for these parameters, as the database-scoped versions were ignored anyway.

[theypsilon]

Downloader:
- Version 2.1 released.
- The time measurement shown at the end of the run now includes the time spent importing modules, making it much closer to real time. Now, there is around a second of mismatch, whereas before, the realtime was around 4.5 seconds more than the output.
- The loading of the internal store now also happens in parallel, which makes the process a bit faster in short runs.
- Optimized the database processing by removing support for the deprecated |-paths. If your database has a |-path, it will be converted to the new format on the fly. The new format is documented in the custom-databases.md document since the previous version.
- Adjusted default value for downloader_threads_limit from 20 to 3, to improve efficiency of short-runs.
- Fixed a bug that affected new users or users with custom launchers.
- Fixed a bug that prevented PNG images from rendering correctly. Images in the docs/ will now display normally.
- The reboot wait, which was significantly reduced in Downloader 2.0, is now longer for Linux updates to prevent issues. However, it is still shorter than in Downloader 1.8 for this scenario.

[spark2k06]

PCXT:

- Fine adjustment of CRT vertical and horizontal offsets

In addition, the selected CGA mode (hres_mode) is taken into account internally so that the offset values do not have to be readjusted according to the mode displayed on the screen.

[Sorgelig]

MacPlus:
-Audio fix: when sound output is disabled, drive output high (darylrichards).
- Update keyboard scancodes.
- Updated framework.