fix(ci): resync the bot prompts with the repo and close the gaps an audit found

The three prompts still enforced the comment ban CLAUDE.md replaced with
the 2-line cap on Aug 1 (1ff90c5b), so the review bot would flag every
legitimate short comment; frontend/CLAUDE.md and CONTRIBUTING.md carried
the same stale rule. The PR reviewer's recipe for reading a post-change
file (headRefOid + pr diff) was unfulfillable with its allowlist - it now
fetches refs/pull/N/head and reads blobs via git show, object-only, no
checkout. Conventions the reviewer checks now include the unchecked docs
openapi.json copy step, the docs/lib/xray third link implementation, the
both-ways route contract, and the i18n dead-key half of the rule.

Also: drop the SUBPROCESS_ENV_SCRUB=0 override on the two untrusted-input
jobs (the mention job proves gh works scrubbed); teach the triage prompt
the issue forms (pre-applied labels, required fields, no re-asking); add
a security-report exception plus SECURITY.md so vulnerabilities are not
confirmed publicly; add a clarification follow-up job so a reporter's
reply to "clarification needed" is actually processed; review PRs again
on ready_for_review and skip drafts; stamp the reviewed head SHA so
force-pushes visibly date a review; scope gh issue/pr edit to label and
title flags; per-job concurrency; comment guards now match the actual
bot login after the run started; artifact names survive re-runs; the
mention prompt's repo map and env-var facts corrected (XUI_PORT,
XUI_TUNNEL_HEALTH_*, distro env files, memory.high, encrypt-tokens).
The bug and feature forms also referenced a "needs triage" label that
does not exist in the repo and was silently never applied - dropped.

SECURITY.md

@@ -0,0 +1,22 @@
+# Security Policy
+
+## Reporting a vulnerability
+
+Do not open a public issue for anything you believe is exploitable — an
+authentication bypass, remote code execution, injection, secret or
+credential exposure, privilege escalation. A public report gives attackers
+a head start against every 3x-ui deployment.
+
+Instead, use GitHub's private vulnerability reporting: open this
+repository's **Security** tab and click **Report a vulnerability**. Include
+the affected 3x-ui version, reproduction steps, and the impact you see.
+You will receive replies in the advisory thread.
+
+There is no bug-bounty program. Fixes ship in the next release, and the
+advisory is published after a fixed version is available.
+
+## Supported versions
+
+Only the latest release receives security fixes. Update with the install
+script or your package channel and confirm the problem still exists before
+reporting.