docs/plans: regen-verify-gate required facts (durable carrier for deleted emit_rust caveat)

ROADMAP.md

@@ -205,7 +205,7 @@ Adjacent lane — algorithmic-cost rewrite engine (the §3 construction design;
 - [ ] emitted crate `cargo build`s green (Route-A last mile)
   - [ ] real fixed point: `content_hash` stage1==stage2 (dissolve placeholder hashes)
     - [ ] wire `regen_stage0 --verify` lockstep gate into CI — enforces no stage0 hand-edits ← **keystone**
-      - [ ] dissolve seed hand-patches (`patch_*` / `HAND_MAINTAINED_STAGE0_FILES`)
+      - [ ] dissolve seed hand-patches (`patch_*` / `HAND_MAINTAINED_STAGE0_FILES`) — the `emit_rust` hand-sync caveat the gate must reproduce: [required facts](docs/plans/regen-verify-gate-required-facts.md)
   - [ ] TypeScript to first-class (beyond the `add` slice)
   - [ ] seed-honesty discharge (Diverse Double-Compiling)
   - [ ] collapse `src/v1` → pinned v2-emitted seed; delete the 154k hand-written lines (terminal, not a big-bang `rm`)

docs/plans/regen-verify-gate-required-facts.md

@@ -0,0 +1,42 @@
+# regen --verify gate — required facts (carried from the deleted emit_rust header)
+
+Status: parked design row. Pins the load-bearing operational facts that the
+`v1_compiler_emit_rust.rs` header carried before the codebase-wide comment ban
+deleted it (deletion was operator-directed; git history holds the full original
+at `git show <pre-ban-sha>:src/v1/stage0/src/v1_compiler_emit_rust.rs`). A
+comment described the regen hazard but enforced nothing — the structural home for
+the fact is this gate. Breadcrumb: `node://adhoc-80af9ff8-40f` (#5514 deferral).
+
+## Why this row exists
+
+`src/v1/stage0/src/v1_compiler_emit_rust.rs` is a **hand-synced mirror** of the
+`.dag` authority, **not** a clean regen fixpoint. There is no `regen --verify`
+gate, so a blind regen would silently overwrite the two hand-resolved drifts
+below and regress the wire-policy fix. The protection was always absent; this row
+makes the fact durable so it rides the gate when it lands.
+
+## The two hand-resolved local drifts (must be reproduced by a faithful regen)
+
+1. **cargo header inlined** — the file inlines its cargo header rather than
+   importing the deliberately-unwired `extdeps_cargo_version` orphan module.
+2. **policy ref/value alignment at `wire_value_serialize.rs`** — the wire-policy
+   reference/value alignment is hand-resolved here; a naive regen loses it.
+
+All other emitted modules stay byte-identical to the committed seed.
+
+## Deferral provenance (#5514, verbatim)
+
+"regen-write still emits a non-building seed from ~150 emitter-completeness gaps;
+the clean green regen fixpoint is deferred, converges with the Route-A emitter
+self-host." A faithful full regen wires the deliberately-unwired orphan std
+modules (`std_measure`, `std_algebra`, `std_realization_schedule`,
+`std_machine_constraints`, `std_integer`, `extdeps_version_semver`,
+`extdeps_cargo_version`) and surfaces ~150 latent emitter-completeness gaps
+(std numeric / measure-tower generic emission).
+
+## Dissolution trigger
+
+§7 fixpoint convergence with the Route-A emitter self-host — when
+wire-all-emitted-modules → regen-equals-committed is in reach, the
+`regen --verify` gate (a wall: a clean regen must reproduce the committed seed
+bit-identically) becomes buildable and this row dissolves into it.