docs(wails): move the prose onto v3 and record Phase 7

CLAUDE.md gains a Packaging section for the four Taskfile facts the
recipes just needed — wails3 on PATH by bare name, no -ldflags on
`wails3 build`, bin/ not build/bin/, and bundling as its own step —
plus how build/'s platform metadata generates from build/config.yml and
what that refresh overwrites.

Its lifecycle, bindings, harness, events and CI sections were still
describing v2. The events one matters most: the rule to emit through
events.Emit survives, but its justification is now the weaker one, and
saying so is the point of the migration. v2's runtime.EventsEmit
log.Fatalf'd on any context not carrying the runtime; v3's emit takes
no context at all, so what is left to pin is that one emit path is what
lets emitStatus drop an unchanged payload for every caller at once.

README told a contributor to `go install wails/v2/cmd/wails` and
apt-get libgtk-3-dev/libwebkit2gtk-4.1-dev; the CLI is vendored and the
stack is GTK4 + WebKitGTK 6.0. Two comments claiming Xvfb and one
claiming frontend/wailsjs go with them.

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

README.md

@@ -78,16 +78,25 @@ YellowJacket is built with [Go](https://go.dev/) and a
 | Go | 1.25+ |
 | Node.js | 22+ |
 | pnpm | 10+ |
-| Wails CLI | v2 (`go install github.com/wailsapp/wails/v2/cmd/wails@latest`) |
+| Wails CLI | v3 — vendored, no install needed (`go tool wails3`) |
 
-On Linux, install the system libraries Wails needs:
+The Wails v3 CLI resolves from the `tool` block in `go.mod`, so there is nothing
+to install globally; `make setup` fetches it with the rest of the tooling.
+
+On Linux, install the system libraries Wails needs. v3 builds against GTK4 +
+WebKitGTK 6.0 by default:
 
 ```bash
-sudo apt-get install libasound2-dev libgtk-3-dev libwebkit2gtk-4.1-dev
+sudo apt-get install libasound2-dev libgtk-4-dev libwebkitgtk-6.0-dev   # Debian/Ubuntu
+sudo pacman -S alsa-lib gtk4 webkitgtk-6.0                              # Arch
 ```
 
-macOS and Windows need no extra system packages. Run `wails doctor` to check your
-environment.
+A machine without `webkitgtk-6.0` can still build with `-tags gtk3` against the
+older WebKit2GTK 4.1 stack, but that is an escape hatch, not what CI or a
+release builds.
+
+macOS and Windows need no extra system packages. Run `go tool wails3 doctor` to
+check your environment.
 
 **Build**