Header-only control token, masked secrets, loopback default (v0.9.9)

Finishes the small items of the security audit in
docs/prs/2026-07-08-PR#000: TODO 3, 4 and 7.

The three mutating endpoints of BuildsApiController no longer accept the
control token as a `token` query parameter — only the X-GitTally-Token
header, which the bundled UI has always used. URLs end up in access logs,
proxy logs, browser history and Referer headers, and the token never
expires, so a historical log capture would yield a valid credential.

`config:print` masks git.token as `***` on both the raw and the --full
path and names the new --show-secrets flag in a leading YAML comment, so
the output stays parseable when piped. The setup script points at
--show-secrets where it used to steer the operator to the plain token.

`server.bindAddress` now defaults to 127.0.0.1: neither the UI nor the
API authenticates read access, so reaching GitTally should require the
host's reverse proxy. Existing .gittally.yml files keep their explicit
value; the managed nginx container needs `0.0.0.0` set deliberately,
which is noted in the release notes, docs/configuration.md and
docs/deployment.md.

Released as v0.9.9, which also carries the previous two commits.

Co-Authored-By: Claude <noreply@anthropic.com>

build.gradle.kts

@@ -11,7 +11,7 @@ plugins {
 group = "de.hoennig"
 // bump at least the patch version for every deployment, so the UI footer
 // (BuildProperties) and --version identify what is actually running
-version = "0.9.8"
+version = "0.9.9"
 
 java {
     toolchain {