six defects, and a typecheck the repo could not pass

Found by reviewing the plugin rather than running it. Nothing was live — the
table does not exist and the plugin is not installed — so all of these were
waiting for the first person to use it.

── The second unnamed design could not be saved ──

`uniqueIndex(userId, title)`, and every design starts life called "Untitled":
`titleOf` returns it for a document with no title and the API defaults to it. So
the first saved, the second collided, and the insert threw under a panel that
could only say "Changes are not being saved." Renaming one design to match
another did the same.

Two designs may share a name, as files and notes and dashboards do. Nothing looks
a design up by title, so uniqueness bought nothing. The index is now ordinary and
on the columns the list query actually uses.

The lesson from `dashboards.id` that the schema comment cites is that a key must
be scoped to its owner. `userId` on the row does that; making the pair unique as
well imported the collision it was citing, one account at a time.

── New did not start a new design ──

It cleared `?doc=`, and no parameter already means "open what I had last",
answered with `/documents/latest`. So New handed back the design on screen and
pointed the next save at its id. There is a `new` sentinel now, in its own module
because both panels read it and neither owns it.

── Two ways the load effect raced the debounced save ──

Changing `?doc=` does not unmount the panel, so the unmount flush never ran for
it: an edit made within the debounce and navigated away from was written after
`latest.current` had been replaced, which is to say never.

And the first save of a new design puts its id in the URL, which lands in the
same effect — re-reading the row overwrote in-memory state with the copy the
server had just been given, discarding whatever was drawn during the round trip.

The effect now flushes what is pending before it reads, and does not re-read a
document it already holds. The editor is keyed on a load generation rather than
on `row?.id`, which could not express "blank again" and left the previous design
on screen with `rowId` cleared underneath it.

── The typecheck ──

354 of the 355 errors were upstream's tree measured against this platform's
settings, which it was never written for. `bunx tsgo` is how this repo is kept
clean and it could not be clean while this plugin existed. `exclude` does not
help: adapter.ts imports the tree back in. So vendor.sh marks each vendored file
unchecked in the same deterministic pass that rewrites its imports. Types still
resolve; only the errors inside those files are silenced, which is what the
adapter already says the seam is for. Whole repo: 0.

── PROVENANCE.md understated what is done to the copy ──

It said "the one edit vendor.sh makes" and described the import rewrite. It also
runs apply-host.py, which places our own lib/host.ts and wires three export
paths. Four files are not upstream and the document whose job is making the copy
trustworthy did not say so. It lists all four now.

Also: web/host.ts imported a path only correct at its destination, so the file
could never typecheck where it is edited — apply-host.py rewrites that line when
placing it, and re-marks the placed copy, which it overwrites after vendor.sh has
marked it. PUT is no longer full-replace: omitting `title` renamed a design to
"Untitled" and omitting `ui` nulled it, a trap set for the second caller. And a
document is bounded at 4 MB, measured in bytes, where the title was capped at 200
and the document at nothing.

web/vendor/PROVENANCE.md

@@ -25,10 +25,24 @@ keep model-provider API keys in `localStorage`, which is not how anything here s
 faithful copy carrying an unused module beats a doctored one that cannot be re-vendored. They are
 inert without a key, and the shell does not surface them.
 
-## The one edit `vendor.sh` makes
+## What is NOT upstream in this directory
 
-Every `@/lib/…` and `@/components/…` import is rewritten to a relative path. This platform already
-binds `@/*` to `src/apps/officer-web` and `@/components/*` to its own shared components, so an
-unrewritten import resolves to the WRONG module rather than failing — silent breakage.
+Four files differ from the clone, and this list is the whole of it. Anything else that does not
+match upstream is a mistake.
 
-The rewrite is deterministic, so a re-vendor produces a readable diff of upstream's real changes.
+**Every `.ts`/`.tsx` file — the import rewrite.** Every `@/lib/…` and `@/components/…` import
+becomes a relative path. This platform already binds `@/*` to `src/apps/officer-web` and
+`@/components/*` to its own shared components, so an unrewritten import resolves to the WRONG
+module rather than failing — silent breakage.
+
+**`lib/host.ts` — ours, not upstream's.** Upstream reviewed the host-adapter contract on
+lnkiai/m3e-canvas#56 and declined to carry it for now, so it is written here and placed by
+`scripts/apply-host.py`. The canonical copy is `web/host.ts`; this one is a copy of it.
+
+**`Canvas.tsx`, `components/PromptPanel.tsx`, `components/Inspector.tsx` — host hooks wired in.**
+`apply-host.py` matches on structure rather than context so upstream can reformat freely, and it
+stops loudly when an anchor genuinely disappears. All three export paths are wired, which is what
+upstream said a complete version needs.
+
+Both transformations are deterministic, so a re-vendor produces a readable diff of upstream's real
+changes rather than of the edits above.