refactor(ui-core): the frontend draws lucide again

[YaelAnaya]

The frontend draws lucide-react again. One hundred and ninety-six references over
thirty-nine files, both manifests, the lockfile, the configuration, the gate that
holds it, the documentation that describes it, and the ten reference images that
photograph it.

This reverses the icon half of #771 and #774. Those changes were sound when they
were made; this is a product decision to draw a different set, not a defect being
corrected, and everything that recorded the old choice moves with it rather than
being left to contradict the code.

The migration

Seventy-two distinct glyphs, every one resolved against the installed
lucide-react before anything was rewritten — the same discipline the migration in
the other direction used, and for the same reason: icon names are not guessable
between libraries. None was missing.

files rewritten        39
references rewritten   196
distinct glyphs        72  (72 mapped, 0 missing)

Two details the mapping alone could not carry.

The rewrite is keyed on names, not on a prefix. The demo's tool strip has a
local component called IconButton. A blanket Icon* rewrite would have renamed a
component belonging to neither library.

ProjectNav imports the icon component type, and the libraries spell it
differently — Tabler's Icon against lucide's LucideIcon. That surfaced as a
compile error rather than as anything subtler, and the fix moved the type while
leaving the local icon: Icon destructuring alone, which is a value.

The geometry glyphs return to the spelling they had before: Spline for the polygon
and Waypoints for the lane. Worth one note, since the migration the other way made
a point of this: GeometryIcon argues that a lane must read as an open path and
that Spline is the closed shape above it. That reasoning is the original code's and
is coherent again as written — but lucide's Spline does render as an open curve, so
if the closed/open distinction matters more than the restoration does, that is a
separate and much smaller change to make deliberately.

The configuration, and one honest divergence

components.json says iconLibrary: lucide. The strict shadcn schema accepts the
value — checked with rawConfigSchema.safeParse rather than assumed, since that
schema rejects a field it does not define rather than ignoring it.

The preset does not. b3bXyyPdWj decodes iconLibrary: tabler, and DESIGN.md
still says so on the line that reports the decode, because falsifying that to match
the product would make the document lie about the CLI's own output. What changed is
that the configuration now diverges from the preset on this one property, and both
DESIGN.md's Source of Truth and the architecture note record the divergence in
the section built for exactly this distinction. It is the only place where reading
the preset and reading the configuration give different answers, and nobody should
have to discover that by diffing them.

The gate

It guarded lucide; it guards Tabler now. The rule it holds is one icon library
rather than one particular library — what costs a reader is two sets on a screen,
where the same idea arrives at two weights and two grids — so the guarded name is
the only thing that changes when the choice does, and the docstring says that.

Both halves were re-proved by breaking them: a manifest that declares the other set
fails, and a source that imports it fails naming the file.

projectNav's own assertion was written to prove the migration away from lucide,
and as written it would have passed for a file that stopped drawing icons at all. It
asserts both directions now.

The baselines

All ten reference images hold icons, so all ten changed. They were regenerated in
the canonical container, opened and read rather than accepted from a green run, and
the suite passes three consecutive runs against them with no further update.

Them going red on an icon swap is the gate working. Regenerating was the answer only
because the change was intended.

Test plan

Every command ran inside Docker/Linux; no repository validation ran natively on the
host.

install (pnpm install --frozen-lockfile, from an empty tree)  PASS
build (pnpm -r build)                                         PASS
@visionset/ui-core lint (incl. typecheck)                     PASS
@visionset/ui-core test                                       PASS
@visionset/app build                                          PASS
@visionset/app lint (incl. typecheck:e2e)                     PASS
@visionset/annotator test                                     PASS
pnpm test:scripts                                             PASS
pnpm version:check                                            PASS

full browser suite (all projects)                             276 passed
visual project, three consecutive runs                        10 / 10 / 10

Overlap

DEPENDENCY OVERLAP with #775. It edits frontend/app/package.json,
frontend/ui-core/package.json and pnpm-lock.yaml — the same three files, and it
raises lucide-react to 1.33.0, which is the version this branch resolves to
anyway. Whichever lands second wants a rebase rather than a merge resolution.

#775 also raises shadcn from 4.18.0 to 4.19.0, and that package is a runtime CSS
dependency here. If the bump moves base styles, the visual suite goes red on merge —
which is the gate working, and wants the diff images read rather than a blind
regeneration.

Scope

Routes changed:            No
Product IA changed:        No
Backend / wire / domain:   No
Design tokens changed:     No
Primitive API changed:     No
Annotator behaviour:       No

Nothing about the product's behaviour changes here. What changes is which set the
glyphs come from, and every record of that choice.