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>

tools/setup-gittally-instance

@@ -275,7 +275,8 @@ Done. GitTally config for $hostname is in place.
 Verify and start on this host:
 
     cd $REPO_DIR
-    java -jar $JAR_PATH config:print --full     # check the effective config + git.token
+    java -jar $JAR_PATH config:print --full     # check the effective config (git.token masked)
+    java -jar $JAR_PATH config:print --full --show-secrets   # ... including git.token in clear text
     java -jar $JAR_PATH server                  # or: java -jar $JAR_PATH init --systemd
 
 Note: GitTally binds to $hostname:${GITTALLY_ARTIFACT_SERVER_PORT:-18080} over plain HTTP.