refactor: comments state current behavior, not project history

Comments across the tree justified the code by pointing at a Rust
implementation that is no longer in the repository, citing files and line
numbers (config.rs:132, schema.rs:26-54, reader.rs:42) that cannot be
opened, plus crates and datasets that are equally gone. A reader could not
check any of it.

Every invariant those comments carried is kept and restated so it stands on
its own: the bytewise sort that decides which row survives a duplicate exam
number, the literal U+0300..U+036F range that must match the site's toAscii,
the trailing space in "SINH ", the BIFF and shared-string corrections, the
VACUUM-after-COMMIT rule, the deploy-from-main guard.

The reader's contract is now anchored to the frozen oracle in
parser/testdata, which still exists and is still checked, rather than to the
tool that originally produced it.

TestDDLMatchesRust becomes TestDDLIsFrozen: it compares against a copy of
the DDL inside the test and never read schema.rs, so both the name and the
failure message were misleading.

ToAscii no longer claims the d-replacement must precede lowercasing. Both
cases map to 'd' and ToLower runs last, so the order has no effect.

assembler/internal/site/site.go

@@ -47,7 +47,7 @@ func DefaultPaths(root string) Paths {
 // BuildWeb runs the Vite build.
 //
 // Shelling out to npm is not a wart: Vite is a Node tool, and web/ is the only
-// npm project left in the repository. This stage owns the sequencing, not the
+// npm project in the repository. This stage owns the sequencing, not the
 // bundling.
 func BuildWeb(p Paths) error {
 	cmd := exec.Command("npm", "run", "build")

assembler/internal/verify/verify.go

@@ -5,9 +5,8 @@
 // out — but a change in transform or writer logic can alter what is in those
 // rows while both of those still pass. This is what catches that.
 //
-// It was written as the gate for the Rust-to-Go parser migration and works for
-// any two builds: before and after a refactor, or a re-crawl against the
-// databases already published.
+// It works on any two builds: either side of a refactor, or a re-crawl against
+// the databases already published.
 package verify
 
 import (