Implementation plan: wave-based decomposition; waves 1-2 decomposed (11 tasks)

docs/plans/implementation.md records the wave structure (core ->
substrate fork || pg engine -> sqlite engine -> contract suite ->
release), the decided points (contract-suite layout = option (a),
engine-tests vs equivalence-suite split, no CI, mem-engine/fuzzing
deferrals surfaced), and the review-gate rhythm.

Wave 1 (foundations): workspace scaffold, core errors/validation,
value types, trait surface, contract-suite scaffold (+ADR-022),
review gate.
Wave 2 (substrate fork): fork scaffold/provenance, connection+watcher
port, queue-op re-derivation on contract v1, provenance/floor close,
review gate.

tasks/fork-port-connection-watcher.md

@@ -0,0 +1,102 @@
+---
+id: fork-port-connection-watcher
+name: Fork port — connection architecture + watcher machinery
+status: pending
+depends_on: [fork-substrate-scaffold]
+scope: broad
+risk: medium
+impact: component
+level: implementation
+tags: [wave-2, substrate]
+---
+
+## Description
+
+Port the connection/watcher half of honker-core into
+`alkstore-sqlite/src/substrate/` — the machinery the quality read
+verified clean and ADR-011 §scope inherits near-verbatim. Source:
+`/workspace/honker/honker-core/src/` @ `f4e53c6` (`lib.rs` ~4k lines,
+`shm_watcher.rs`, `kernel_watcher.rs`).
+
+**Port (the kept half, ADR-011 / quality-read §6):** the PRAGMA/WAL
+open posture + `set_journal_mode_wal` retry logic; `Writer`; `Readers`;
+the polling watcher + `SharedUpdateWatcher` + `WatcherDeathGuard` +
+`stat_identity` dead-man's switch; the `in_savepoint` /
+`UnwindUndo` mutation-discipline machinery; the REAL-coercion arg
+helpers; the notify scalar + notifications table; stream functions;
+lock functions.
+
+**Port deltas (ADR-012 §4 — the only deliberate behavior changes):**
+
+- W-1: bounded reconnect backoff in the watcher loop (no ~1000
+  open-attempts/sec on a vanished db file).
+- W-2: watcher spawn becomes fallible; callers (the engine, wave 3)
+  surface the failure at open time.
+- Dead-man's switch: the db-file-identity-change panic is replaced by
+  a deliberate watcher-fatal death (log the precise diagnostic, exit
+  through the ordinary death path); `WatcherDeathGuard`'s
+  death-closes-subscribers behavior unchanged.
+
+**Drops (do not port):** `cron.rs`; the `kernel-watcher` /
+`shm-fast-path` experimental watcher backends and their optional deps
+(`notify`, `memmap2`, `libc`); the rate-limit and result tables; the
+superseded queue functions (the queue half is re-derived in a separate
+task).
+
+**Table naming:** `_honker_*` → `__alkstore_*` across the ported
+storage surface (ADR-011; ADR-010 §8 authorization). No online
+migration machinery — fresh bootstrap only (ADR-012 §5).
+
+**Fidelity posture (ADR-012 §3):** keep upstream's module structure and
+internal function names for the kept half, including lineage tokens
+(`Writer`, `run_poll_loop`, `in_savepoint`). Renames confined to the
+table family and the hygiene deltas. The port is mechanical where
+possible — the diff against the lineage must stay reviewable.
+
+**Discipline deltas (family standard, ADR-012 §4):** no comments in
+code (doc comments on the substrate's internal public surface fine),
+no panics in library code (the dead-man's-switch delta is the big
+one), no `unwrap()`/`expect()` outside tests. The substrate stays sync
+— no tokio, no asyncification.
+
+**Bootstrap re-keying (ADR-012 §5):** the fork owns the bootstrap;
+append-column migrations stay; the duplicate-column race swallow is
+re-keyed to `pragma_table_info` verification (present ⇒ benign race,
+absent ⇒ propagate) — upstream's error-string matching is not
+inherited.
+
+**Tests (the floor, ADR-011):** inherit honker-core's suites for the
+ported machinery — PRAGMA/WAL, watcher lifecycle + failure handling,
+savepoint + multiprocess pressure — adapted to the new table names and
+the three port deltas. These run as engine-crate tests (the substrate
+is not separately testable through a public seam).
+
+## Acceptance Criteria
+
+- [ ] Kept machinery ported with upstream names/structure preserved;
+      diff vs. lineage reviewable (the wave-2 review checks this)
+- [ ] Three watcher deltas applied; dead-man's switch exits without
+      panicking; `WatcherDeathGuard` still closes all subscribers
+- [ ] Dropped machinery absent (no cron, no experimental watchers, no
+      rate-limit/result tables, no superseded queue functions)
+- [ ] Table family is `__alkstore_*`; bootstrap fresh-only; race
+      swallow re-keyed to `pragma_table_info`
+- [ ] Inherited test suites green (adapted); watcher-death-closes-
+      subscribers test present
+- [ ] Substrate is sync (no tokio imports); no panics/`unwrap()` in
+      library code; clippy `-D warnings`, fmt clean
+
+## References
+
+- docs/architecture/decisions/011-sqlite-substrate-fork.md (scope register)
+- docs/architecture/decisions/012-forked-substrate-design.md §3–§5
+- docs/research/quality-read-honker-core.md §6 (the fork scope), §2 (watcher verdict)
+- /workspace/honker @ f4e53c6 (the lineage)
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion