docs(virtual_jaguar): update Virtual Jaguar page for core v3.0.0

[JoeMatt]

The Virtual Jaguar page had drifted a long way from the core. This brings it in line with the shipped v3.0.0 release (the master/buildbot core).

Author

Leads with Joseph Mattiello, matching the core's own .info file (authors = "Joseph Mattiello|David Raingeard|Shamus").

Extensions

Added .cue and .cdi for Jaguar CD, and a note that bare .iso images are refused at load time — a 2048-byte-sector ISO can't represent a Jaguar CD's multi-session layout, so no retail disc boots from one.

New BIOS section

Both Jaguar CD BIOS images with md5sums, flagged clearly as optional overrides — the core embeds them and no BIOS file is required:

Filename	md5sum
[BIOS] Atari Jaguar CD (World).j64 (retail)	77cd95c7ad06a39f4c59995094aa10f9
[BIOS] Atari Jaguar Developer CD (World).j64 (developer)	578de34498cb9a40c5368b6f5ca80484

The console boot ROM is deliberately not listed — it's never loaded from the system directory, so listing it would send people hunting for a file the core ignores.

Features table

States, Rewind, Netplay, RetroArch Cheats and Native Cheats flip from ✕ to ✔. The core reports zero serialization quirks, implements RETRO_ENVIRONMENT_SET_NETPACKET_INTERFACE, and implements retro_cheat_set / retro_cheat_reset.

Directories

The separate *.cdrom.srm no longer exists — cartridge EEPROM, CD EEPROM and the 128 KB Memory Track NVRAM all round-trip through one frontend-managed .srm.

Core options

Rewritten and grouped into the core's nine categories. Doom Res Hack is removed — the option was deleted upstream once the underlying resolution handling was fixed — along with its two screenshot admonitions, which would otherwise be orphaned.

Added: CD Boot Mode, CD BIOS Type, CD Read Speed, Memory Track, the four Network Link (JagLink/CatBox) options, Crash Detect, CD Trace and DRAM Timing, plus the per-port input remapping options. No new image references were added, since those files don't exist in this repo.

Compatibility

The per-game issue tables are removed. The full commercial cartridge library and every Jaguar CD title now boot and run, so the old table was mostly stale entries (Wolfenstein 3D, Iron Soldier, Iron Soldier 2, Pitfall, Doom's resolution hack…). Per-game issues are tracked on the core's issue tracker, and keeping a second copy here just guarantees one of them is wrong. The section now points there, plus at the CD boot matrix in the core repo.

This also drops the two orphaned screenshot admonitions (cyber.png, ninja.png) that only the removed table referenced.

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This documents v3.0.0 specifically. The options currently only on develop (Jaguar GameDrive, M68K/RISC clock scale) are intentionally left out until they ship.

[Copilot]

Pull request overview

Updates the Virtual Jaguar core documentation to reflect the current libretro Virtual Jaguar core v3.0.0 behavior, especially around Jaguar CD support, BIOS handling, features, and the expanded core options set.

Changes:

• Refreshes background/author info and adds Jaguar CD extensions plus an .iso load-time limitation note.
• Adds a new BIOS section documenting optional Jaguar CD BIOS override filenames and MD5 hashes.
• Rewrites the core options section into categories (Video, BIOS & Boot, CD-ROM, Network Link, Input, Diagnostics, Timing) and updates compatibility notes.

Suppressed comments (1)

docs/library/virtual_jaguar.md:203

• This line reads like a single core option named "Port 1/2 > RetroPad (button)", but the core exposes one option per port and per RetroPad input (e.g., Port 1 > RetroPad Up, Port 2 > RetroPad Up, etc.). Rewording this bullet as a grouped/patterned set of options makes it clear there isn't a single option/key users can look up.

- **Port 1/2 > RetroPad (button)** [virtualjaguar_p1_retropad_*] [virtualjaguar_p2_retropad_*]

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[JoeMatt]

Good catch — fixed. The page now has separate Input Port 1 and Input Port 2 sections listing the real option keys (virtualjaguar_p1_numpad_to_kb / virtualjaguar_p2_numpad_to_kb, and virtualjaguar_p1_retropad_* / virtualjaguar_p2_retropad_*), with a concrete example key for each so the names are searchable. Port 2's entries point back at Port 1 for the value list rather than duplicating it.