Stop documenting the recovery API that 1.6.0 deleted

Disc::sweep, Disc::patch, Disc::copy, SweepOptions and PatchOptions have
zero occurrences in src/ — recovery moved to freemkv-engine — but they were
still documented in 30 places across README.md, TROUBLESHOOTING.md, six
files under docs/, seven src/ doc comments and a Cargo.toml comment.
README.md is the crate's GitHub front page and carried a full multi-pass
code example that cannot compile.

Two of the src/ references were intra-doc LINKS to deleted items
([`disc::Disc::copy`], [`disc::Disc::patch`] in scsi/mod.rs). They produced
no warning on a normal `cargo doc` only because they sit on pub(crate)
items; `--document-private-items` reports both, and they are gone now.

The README example is deleted rather than rewritten against the engine's
API: libfreemkv documenting a downstream crate's API on its own front page
is the drift that produced this, and it cannot even depend on it. The src/
references become plain code spans naming freemkv_engine::recovery::* —
deliberately not links, for the same reason.

docs/rip-recovery.md was 202 lines about relocated code. It now documents
only what this crate owns — Drive::read, SenseFamily, DiscStream's adaptive
batch halving — plus the read-path design constraints, which belong with the
code that enforces them, and points at freemkv-engine/src/recovery/ for the
strategy. api-design.md's module tree is regenerated from the real src/disc/
and src/drive/ layouts instead of hand-patched; it had listed sweep.rs,
patch.rs, mapfile.rs and read_error.rs, none of which exist.

Three stale facts surfaced while rewriting and are corrected: the read
timeouts are 10 s / 60 s, not the documented 1.5 s / 30 s; Drive::reset and
SgIoTransport::reset no longer exist at all, so "no SCSI reset from any read
path" is now stated as the stronger fact it has become; and verify_title,
listed as a progress-emitting operation, was removed entirely.

CHANGELOG.md keeps its references — those are the historical record of the
releases that shipped the API.

docs/api-design.md

@@ -170,17 +170,20 @@ libfreemkv/src/
 │   ├── writeback_file.rs  WritebackFile (was crate::io::Writer)
 │   └── writeback.rs    sync_file_range pipeline
 ├── drive/              Drive (open, init, single-shot read)
-│   ├── mod.rs          Drive struct, init, read (single-shot), reset, eject
+│   ├── mod.rs          Drive struct, init, read (single-shot), eject
 │   ├── capture.rs      Raw drive SCSI capture (INQUIRY/GET_CONFIG) for contribution
 │   ├── linux.rs        Linux drive discovery
 │   ├── macos.rs        macOS drive discovery
 │   └── windows.rs      Windows drive discovery
-├── disc/               Disc (scan, titles, AACS setup, sweep, patch)
-│   ├── mod.rs          Disc struct, scan, titles, formats; Disc::copy + Disc::sweep (Pass 1)
-│   ├── sweep.rs        Pass 1 internal helpers (pub(super))
-│   ├── patch.rs        Disc::patch (Pass N retry over mapfile)
-│   ├── mapfile.rs      ddrescue-format mapfile
-│   └── read_error.rs   ReadCtx / ReadAction state machine
+├── disc/               Disc (scan, titles, AACS setup, per-format parsing)
+│   ├── mod.rs          Disc struct, scan, titles, formats
+│   ├── bluray.rs       Blu-ray / UHD scanning (MPLS/CLPI-driven)
+│   ├── dvd.rs          DVD-Video scanning (IFO-driven)
+│   ├── hddvd.rs        HD-DVD scanning
+│   ├── extract.rs      Per-extent content extraction
+│   ├── encrypt.rs      Encrypted-range mapping for content reads
+│   ├── dvd_audio_probe.rs   DVD audio-stream probing
+│   └── pgs_forced_probe.rs  PGS forced-subtitle probing
 ├── scsi/               SCSI transport (Linux SG_IO, macOS IOKit, Windows SPTI)
 ├── unlock.rs           Unlocker trait + registry (pluggable unlock seam)
 ├── aacs/               AACS decryption (handshake, keys, keydb, decrypt)