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>

src/main/kotlin/de/hoennig/gittally/commands/InitCommand.kt

@@ -125,8 +125,10 @@ class InitCommand(
               publicBaseUrl: ""
               # HTTP port of the `server` subcommand
               port: 18080
-              # bind address of the `server` subcommand
-              bindAddress: 0.0.0.0
+              # bind address of the `server` subcommand; loopback only, because the UI and the
+              # API are unauthenticated — use 0.0.0.0 only without a reverse proxy in front
+              # (and with the managed nginx below, which reaches GitTally from its container)
+              bindAddress: 127.0.0.1
               # optional Impressum (legal disclosure) link in the web UI footer; empty hides the link
               impressumUrl: ""
               # Opt-in managed nginx+certbot Docker container for HTTPS, for hosts without