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.

src/mux/disc.rs

@@ -3,7 +3,7 @@
 //! One stream type for all disc sources. The source is a SectorSource —
 //! Drive (hardware) or FileSectorSource (file). DiscStream doesn't care.
 //!
-//! Read-only. For disc→ISO (raw sector copy), use `Disc::copy()`.
+//! Read-only. For disc→ISO (raw sector copy), use `freemkv_engine::recovery::copy`.
 
 use crate::disc::{DiscTitle, Extent};
 use crate::drive::extract_scsi_context;

src/mux/mod.rs

@@ -21,7 +21,7 @@
 //! output.finish()?;
 //! ```
 //!
-//! For disc→ISO (raw sector copy), use `Disc::copy()` instead.
+//! For disc→ISO (raw sector copy), use `freemkv_engine::recovery::copy` instead.
 
 // Public modules — types here are intentionally part of the consumable API.
 pub mod disc;

src/mux/resolve.rs

@@ -16,7 +16,7 @@
 //! | fvi://  | -- | Yes | file path (required) — per-picture video index |
 //!
 //! Bare paths without a scheme are rejected.
-//! For disc→ISO (raw sector copy), use `Disc::copy()` instead.
+//! For disc→ISO (raw sector copy), use `freemkv_engine::recovery::copy` instead.
 //!
 //! Note: `disc://` cannot be opened through [`input`]; it returns
 //! [`crate::error::Error::DiscUrlNotDirect`]. Live-disc input must go