Fork port: connection architecture + watcher machinery into the substrate (ADR-011/012 §3–§5, task fork-port-connection-watcher)

Kept half of the honker-core fork lands in
alkstore-sqlite/src/substrate/ as schema.rs / watcher.rs / ops.rs
(register D-17): PRAGMA/WAL open posture + set_journal_mode_wal retry,
Writer, Readers, the polling watcher family (SharedUpdateWatcher,
WatcherDeathGuard, stat_identity dead-man's switch), in_savepoint/
UnwindUndo mutation discipline, REAL-coercion arg helpers, notify
scalar + notifications table with the ADR-010 §6 at-attach pruning
cap, stream functions, lock functions.

Port deltas (ADR-012 §4): W-1 bounded reconnect backoff
(MAX_RECONNECT_TICKS=100), W-2 fallible watcher spawn (Result; engine
maps to Database at open in wave 3), dead-man's-switch panic replaced
by log-and-exit through the ordinary death path — death still closes
every subscriber (pinned by test, join now Ok). Table family
_honker_* -> __alkstore_* (D-10); duplicate-column race swallow
re-keyed to pragma_table_info (D-11); scheduler cron_expr -> spec;
fresh-only bootstrap, append-column migrations kept, column-order
equality pinned. Drops confirmed absent: cron, kernel/shm backends,
rate-limit/result tables, superseded queue functions (D-01..D-04).
file-id retained for the kept dead-man's switch (D-18).

43 engine-crate tests green (adapted inherited suites + delta tests +
cross-mechanism pressure); cargo build/clippy -D warnings/fmt clean.
PROVENANCE.md register updated to the landed state (D-01..D-20).

alkstore-sqlite/src/substrate/mod.rs

@@ -33,8 +33,23 @@
 //! this directory) is the preservation obligation's carrier;
 //! provenance register: [`PROVENANCE.md`](PROVENANCE.md).
 //!
-//! Scaffold state: this module is intentionally empty of machinery.
-//! The port tasks (`fork-port-connection-watcher`,
-//! `fork-rederive-queue-ops`) land the forked lineage and the
-//! re-derived queue ops here; the register and the license notice are
-//! already in place so the ports land into a finished frame.
+//! Scaffold state: the connection/watcher machinery (the kept half
+//! of the fork, ported by `fork-port-connection-watcher`) lives under
+//! this module below — `schema.rs`, `watcher.rs`, `ops.rs` in
+//! upstream's `lib.rs` / `honker_ops.rs` order. The re-derived queue
+//! ops (`fork-rederive-queue-ops`) land beside them.
+//!
+//! Port state (wave 2): the machinery below is ported but not yet
+//! wired by the engine layer (wave 3 wires `open`, the trait impl, the
+//! seam). A subset of the ported surface is therefore unreachable
+//! until that wiring lands.
+
+#![allow(dead_code)]
+#![allow(unused_imports)]
+
+mod ops;
+mod schema;
+mod watcher;
+
+pub(crate) use schema::{attach_notify, bootstrap_schema, open_conn};
+pub(crate) use watcher::SharedUpdateWatcher;