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

tools/branding.conf

@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+# branding.conf - this plugin's canonical identity.
+#
+# Managed by tools/brand-plugin.sh, read by tools/check-branding.sh. Hand-editing
+# works and is sometimes the quickest thing, but the helper is what keeps this
+# file, the source tree and tools/branding-sites.tsv agreeing with each other.
+# Edit here and you are on the hook for running the checker afterwards.
+
+# --- derivations ------------------------------------------------------------
+# Defined before the values so the defaults below can use them.
+# Package name: lowercased, every run of non-alphanumerics becomes one
+# underscore. Cargo accepts hyphens too and maps them to underscores for the
+# built artifact, which nih_plug_xtask already handles; underscores are used to
+# match the Rust convention.
+_derive_pkg() {
+  printf '%s' "$1" | tr '[:upper:]' '[:lower:]' \
+    | sed -e 's/[^a-z0-9]\{1,\}/_/g' -e 's/^_//' -e 's/_$//'
+}
+# Rust type name: CamelCase, non-alphanumerics dropped.
+_derive_struct() {
+  printf '%s' "$1" | sed -e 's/[^A-Za-z0-9]\{1,\}/ /g' \
+    | awk '{for(i=1;i<=NF;i++) printf "%s%s", toupper(substr($i,1,1)), substr($i,2); print ""}'
+}
+
+# --- the names ---------------------------------------------------------------
+PLUGIN_NAME="Plugin Name"               # the one name everything else derives from
+VENDOR="Your Name"                      # Plugin::VENDOR - the org, not the person
+EMAIL="your@email.com"                  # Plugin::EMAIL
+HOMEPAGE="https://github.com/YOUR-USERNAME/YOUR-PLUGIN-NAME"   # -> Plugin::URL
+DESCRIPTION="A minimal NIH-plug audio plugin"                  # Cargo description
+
+# What the plugin does *now*. No codename, no "prototype", no "v2 rewrite" -
+# hosts show this to users who never knew any of that. check-branding.sh
+# enforces the mechanical half by rejecting retired names and the repo codename.
+CLAP_DESCRIPTION="Your plugin description"
+
+# --- frozen identity ---------------------------------------------------------
+# Hosts key saved projects and presets off these two. Change either and every
+# existing session silently loses the plugin: the track comes up empty, with no
+# error. Choose once before the first release, then never again.
+# brand-plugin.sh refuses to move them without --allow-identity-change.
+CLAP_ID="com.your-domain.plugin-name"   # reverse-DNS, lowercase, no spaces
+VST3_CLASS_ID="Unique16CharId!!"        # MUST be exactly 16 bytes
+
+# --- fixed at repo creation --------------------------------------------------
+# The repository's own name. Deliberately NOT renamed when the plugin is: the
+# repo keeps its development codename while the plugin gets a product name.
+# Recorded only so it can be kept out of user-facing text.
+CODENAME="nih-plug-template"
+
+# Where the two Rust types are defined. A plugin whose params outgrow lib.rs
+# points PARAMS_FILE at src/params.rs.
+LIB_FILE="src/lib.rs"
+PARAMS_FILE="src/lib.rs"
+
+# --- derived unless overridden -----------------------------------------------
+# Set one only when the derivation is wrong or rejected - a name like
+# "206 Prototype" derives to "206_prototype", which cargo refuses because a
+# package name cannot start with a digit.
+#
+# This template overrides three of them, which a real plugin usually will not:
+# its package and type names are the template's own rather than derived from a
+# product name. Delete these three lines after renaming and the derivations
+# from PLUGIN_NAME take over.
+PKG="nih_plug_template"
+STRUCT="MyPlugin"
+PARAMS_STRUCT="PluginParams"
+# DISPLAY="Plugin Name"      # defaults to PLUGIN_NAME
+: "${DISPLAY:=$PLUGIN_NAME}"
+: "${PKG:=$(_derive_pkg "$PLUGIN_NAME")}"
+: "${STRUCT:=$(_derive_struct "$PLUGIN_NAME")}"
+: "${PARAMS_STRUCT:=${STRUCT}Params}"
+
+# --- retired spellings -------------------------------------------------------
+# Must no longer appear in tracked files. An entry is skipped while it is still
+# part of a canonical value above and arms the moment it stops being one, so a
+# rename is self-checking in both directions. brand-plugin.sh appends here.
+STALE="nih_plug_template
+MyPlugin
+PluginParams
+A minimal NIH-plug audio plugin
+Your plugin description
+Plugin Name
+Your Name
+your@email.com
+com.your-domain.plugin-name
+Unique16CharId!!
+YOUR-USERNAME
+YOUR-PLUGIN-NAME
+your-domain"