refactor: move branding into tools/ and drive the checker from a table

Three changes that only make sense together.

**tools/**. check-branding.sh, brand-plugin.sh and branding.conf were
accumulating in the repo root, and a deploy.sh/bat/ps1 set would land
there too. They now live in tools/ and resolve the repo root explicitly
rather than assuming their own directory is it, so they behave the same
however they are invoked.

**One name drives the rest.** branding.conf now derives the package name,
the Rust types and the display name from PLUGIN_NAME, each overridable.
Derivation-by-default removes a class of drift; the override matters
because the derivation is sometimes invalid — "206 Prototype" derives to
"206_prototype", which cargo rejects outright — and because PLUGIN_NAME is
cosmetic while the package name is structural. A display tweak should not
silently rename the crate, its bundle lookup, the CI command and the
lockfile. This template overrides three of them, which a real plugin
normally will not: its names are the template's own rather than derived
from a product name.

An overridden PKG that no longer matches the derivation is reported at
info level, never failed. The override is usually deliberate; a display
rename that forgot the package looks identical from here, and is not.

**The site table is data.** branding-sites.tsv lists every place a name
must appear and in what form; check-branding.sh iterates it instead of
carrying 29 check calls in shell. The scripts are now identical across
every plugin built from this template, with only the table and conf
differing — which matters because the template and codename-206 had
already diverged by two checks, so every sync was a shell merge.

brand-plugin.sh regenerates the rows it owns and preserves the rest, so a
hand-added row for a file this template does not ship survives a rename.
Custom rows are value-substituted like any other tracked file, so they
track the rename rather than going stale — the first cut excluded the
whole table from substitution and got that wrong.

brand-plugin.sh also gained an interactive mode: run it with no arguments
and it prompts for each value with the current one as the default, so
Enter keeps it and a run that answers nothing changes nothing. It only
engages when there is a terminal to ask at, so CI gets the usage message
and exit 2 rather than a hang.

Verified by applying a full rename to a sandboxed copy: 8 files rewritten,
29 owned rows regenerated, 1 custom row preserved and substituted, checker
green at 48/0/7, and the result compiles as bari_206.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WHt4DykxXaQnyaJfyS8KCn

.github/workflows/ci.yaml

@@ -41,7 +41,7 @@ jobs:
       # Cheap and needs no toolchain, so it runs first: a rename that only
       # landed in half the files is worth catching before spending a build on it.
       - name: Branding consistency
-        run: sh check-branding.sh
+        run: sh tools/check-branding.sh
 
       # The default build is CLAP-only; the vst3 feature is opt-in, so both
       # configurations have to be built to know the cfg gates are still correct.