feat(wails): move the frontend onto v3's generated bindings

frontend/wailsjs/ is deleted and frontend/bindings/ takes its place —
a real TypeScript module tree nested by Go import path, generated by
wails3's static analyser rather than by building the app and running
it.  The @go alias absorbs the constant prefix, so a call site imports
'@go/library/library.js' and the codemod over all 93 sites was a
specifier rewrite plus splitting @go/models' namespaces into one
import per package.

The 12 SetContext bindings and the fake `context` model are gone, as
Phase 2's ServiceStartup port promised: 272 methods across 12
services, none of them plumbing.

@runtime/runtime is now a local shim (src/wails/runtime.ts) over
@wailsio/runtime, so the 22 EventsOn imports are untouched.  It
unwraps v3's WailsEvent into v2's callback shape, which is exact here:
nothing in backend/events passes more than one data argument, and v3
only packs arguments into a slice when there is more than one.

v3 tells the truth about two things v2 lied about, and that is most of
the diff.  A Go nil slice really does arrive as JSON null, and a Go
named string type really is an enum; v2 typed them as T[] and string.
utils/binding.ts states the app's actual contract — an absent list is
an empty list — once, at the boundary where it is true, and also drops
the CancellablePromise the app never cancels.  Four test fixtures
widen an enum field back to its value union.

Not done, and Phase 5's to fix: frontend/test/support/wails-fake.ts
still fakes window.go, which v3 does not have, so `make ui-test` is
broken and harness.test.ts fails to compile on EventsEmit.  That test
also asserts v2 ordering that no longer holds — v3's Events.Emit calls
the backend and does not notify in-page listeners at all.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UDCbcCZQepnpSQYJ6SxxZm

Makefile

@@ -100,14 +100,9 @@ ui-visual-update: ## Re-record the screenshot baselines
 ui-setup: ## Install the Vitest browser provider's own Chromium (once)
 	@cd frontend && pnpm install && npx playwright install chromium
 
-# Bindings are generated by `wails`, NOT by `go generate`, so the
+# Bindings are generated by `wails3`, NOT by `go generate`, so the
 # pre-commit codegen check does not cover them: a renamed Go struct
-# field currently surfaces at runtime, in a window.
-#
-# NOTE (plan 009 phase 4): this still checks v2's frontend/wailsjs,
-# which nothing regenerates now that the v2 CLI is gone.  It is
-# excluded from the pre-commit hook until the frontend moves to
-# frontend/bindings.
+# field would otherwise surface at runtime, inside a window.
 bindings-check: ## Fail if the generated bindings are stale
 	@./scripts/bindings-check.sh
 
@@ -130,14 +125,13 @@ commit-check: ## Fail if a commit subject is not a Conventional Commit
 	@./scripts/commit-check.sh $(if $(RANGE),--range $(RANGE))
 
 # v3 generates TypeScript into frontend/bindings/, nested by Go import
-# path, rather than v2's frontend/wailsjs/.  The 93 frontend import
-# sites still point at the old tree, so this writes the new one beside
-# it until plan 009 phase 4 moves them; the chmod dance that used to
-# follow is gone with v2's generator, which wrote its runtime files 755.
+# path, rather than v2's frontend/wailsjs/.  The `@go` alias absorbs the
+# constant prefix, so a call site imports '@go/library/library.js'.
 #
-# The tag set is pinned deliberately: the generator is a static
-# analyser, so it only sees the configuration it is told about, and the
-# one that matters is the one users run.
+# No -f flag: the tag set is the default one, deliberately, because the
+# generator is a static analyser that sees only the configuration it is
+# told about and the one that matters is the one users run.  See
+# scripts/bindings-check.sh for why the other two do not apply.
 bindings: ## Regenerate frontend/bindings from the bound Go services
 	go tool wails3 generate bindings -clean=true -ts -i