docs: reconcile the docs with the externally contributed v0.11/v0.12 work

[LinuxJedi]

An audit of the documentation against the source for everything merged since v0.10.0, focused on the contributed features that landed without their documentation half: the filesys services board (#159-#211), the Z3660 RTG card (#212), the A3000/A4000 machines (#180/#184/#185), and the serial/parallel port work (#138/#147/#221). Each finding was verified against the current code before fixing.

Stale documentation fixed

• peripherals.md still described the filesys handler forwarding DosPackets through a "reserved A-line trap"; filesys: switch the services board from A-line traps to MMIO registers #207 replaced that with MMIO doorbell registers (REG_DOSPKT handled synchronously inside the write).
• chipset.md attributed the Centronics data/strobe to CIA-B -- the exact wiring parallel: audio sampler, on a general parallel-port framework #138 corrected. Data, /STROBE, and /ACK are CIA-A; only BUSY/POUT/SEL sit on CIA-B port A.
• cpu.md reported 68040 write faults in writeback slot 2; since m68k: report 68040 write faults in writeback slot 3 #156 the frame builder stacks them in slot 3 (WB2 is reserved for MOVE16), matching real silicon and the MuGuardianAngel/Enforcer handler protocols.
• AGENTS.md promised a positional disk-image argument that main.rs does not implement (the single positional is the ROM; a second errors). The example now routes the disk through --insert-disk-after, verified to boot AmigaTestKit on both AROS and KS3.1/A1200.
• README / --help called the default machine OCS (the A500 Rev 6A default is ECS Agnus + OCS Denise) and described built-in-defaults startup where a bare invocation opens the launcher; --help also omitted the A1000/A500OCS/A3000/A4000 models and the 68010.
• configuration.md / README pointed at a "Serial" launcher tab that launcher: one I/O Ports tab, Add printer to GUI, "Host Mounts" sub-page #221 merged into "I/O Ports"; guest/services/README.md described a fixed -128 boot priority (now the mount's bootpri) and a handler started on first reference (it is ADNF_STARTPROC, at mount time).

Missing documentation added

• Z3660 RTG, previously covered only in configuration.md: a zorro.md section (autoconfig identity 0x144B/1, 128 MB window layout, VRAM/GFXData offsets), an internals/video.md "RTG scanout" section (native-resolution GPU present, chipset fallback, sprite compositing, pixel-centre screenshot downscale), the launcher's RTG card row in ui.md, the RTG behaviour of capture.screenshot in control.md, and a README feature mention.
• peripherals.md sections for Fat Gary and Ramsey (the lane/mirror decode, COLDBOOT as the Gary detector, the version-register identity and the Ramsey-04/-07 control-bit-4 disagreement) and for the parallel-port peripheral boundary (printer capture with ready-online status lines, the emulated-time audio sampler).
• The services-board per-unit register protocol and the DiagPoint rom_scsi_device_disable cull in peripherals.md, plus the board as product 5 in the manufacturer-ID table.
• Smaller gaps: the tcp-connect serial mode in peripherals.md and README, COPPERLINE_DIAG_A4091 in the debugger env-var table, identify in the example config, drag-and-drop cross-referenced from getting-started, the status-bar hide shortcut noted in its own section, and the Host Mounts four-of-eight launcher limit.

Verified clean

The user-facing config surface needed no fixes: every TOML key in config.rs is documented with correct defaults and accepted values, the [a4091] -> [scsi] break left no stale references, and the ui.md shortcut table matches host_input.rs 1:1.

Verification: full unit suite (1773 passed), cargo clippy and cargo fmt --check clean, myst build --html with no new warnings. Source changes are help-text and doc-comments only (main.rs, config.rs, z3660.rs).

[Copilot]

Pull request overview

Documentation reconciliation pass to bring Copperline’s user/developer docs (and a small amount of user-facing help text/doc-comments) back in sync with features merged since v0.10.0—especially externally contributed work around HostFS/services board, Z3660 RTG, big-box machines, and serial/parallel I/O.

Changes:

• Updated CLI --help, README, example config, and internal docs to reflect current defaults (A500 Rev 6A ECS Agnus + OCS Denise), supported models/CPUs, and current launcher/UI structure.
• Added/expanded documentation for Z3660 RTG (Zorro identity/window layout + scanout/presentation behavior) and big-box peripherals (Fat Gary/Ramsey, parallel port boundary, serial tcp-connect).
• Corrected stale internals docs to match current implementations (services board MMIO doorbells, CIA wiring for Centronics, 68040 writeback slot behavior, handler start semantics/boot priority behavior).

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/z3660.rs	Updates module-level doc comment to reflect implemented RTG board behavior.
src/main.rs	Refreshes --help text for supported models/CPUs and the built-in default chipset.
src/config.rs	Updates config-field docstring to list all supported serial modes.
README.md	Aligns feature list, default startup behavior, and launcher tab naming with current code.
guest/services/README.md	Corrects services board boot priority and handler start timing description.
docs/zorro.md	Adds Z3660 RTG Zorro III board documentation and services-board manufacturer/product table entry.
docs/internals/video.md	Documents RTG scanout/presentation behavior and screenshot downsampling under RTG.
docs/internals/peripherals.md	Adds Fat Gary/Ramsey and parallel peripheral boundary documentation; updates filesys and serial docs to MMIO/tcp-connect reality.
docs/internals/cpu.md	Corrects 68040 writeback-slot documentation to slot 3.
docs/internals/chipset.md	Fixes CIA-A/CIA-B Centronics wiring description.
docs/guide/ui.md	Updates launcher/UI documentation (status bar hide shortcut, RTG mention, host-mount limit notes, validation messaging).
docs/guide/getting-started.md	Adds drag-and-drop disk insertion cross-reference.
docs/guide/configuration.md	Updates launcher tab naming and serial section wording for I/O Ports tab.
docs/debugger/headless.md	Adds COPPERLINE_DIAG_A4091 to the env-var table.
docs/debugger/control.md	Clarifies screenshot behavior when an RTG screen is active.
copperline.example.toml	Adds identify-board note and clarifies RTG default-fit criteria.
AGENTS.md	Fixes positional-argument documentation (ROM-only positional; disks via config/flags).

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