release v0.9.9: install.sh needs no sudo + CVE metadata drift fix

install.sh never escalates to sudo. The installer defaulted to
/usr/local/bin and fell back to `sudo mv`, prompting for a password on
exactly the unprivileged accounts a privilege-escalation tool targets. It
now uses /usr/local/bin only when already writable and otherwise installs
to a per-user $HOME/.local/bin (honoring XDG_BIN_HOME), no sudo ever. An
explicit SKELETONKEY_PREFIX is honored and errors rather than escalating.
The documented one-liner prepends ~/.local/bin to PATH so it resolves on a
fresh login, and the quickstart drops the misleading sudo from --scan /
--audit / --auto.

CVE metadata drift (the failing weekly drift-check):
  - CVE-2022-0492 (cgroup_release_agent) entered CISA KEV 2026-06-02;
    corpus now 13 of 36 modules cover KEV-listed CVEs.
  - CVE-2026-46333 (ptrace_pidfd) gained CWE-269 from NVD (was unclassified
    at module-add time).
Refreshed CVE_METADATA.json, generated cve_metadata.c, and KEV_CROSSREF.md;
README + website KEV counts and version bumped to 0.9.9.

docs/index.html

@@ -4,7 +4,7 @@
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>SKELETONKEY — Linux LPE corpus, VM-verified, SOC-ready detection</title>
-<meta name="description" content="One binary. 41 Linux privilege-escalation modules from 2016 to 2026. 28 of 36 CVEs empirically verified in real Linux VMs. 10 KEV-listed. 151 detection rules across auditd/sigma/yara/falco. MITRE ATT&CK and CWE annotated. --explain gives operator briefings.">
+<meta name="description" content="One binary. 41 Linux privilege-escalation modules from 2016 to 2026. 28 of 36 CVEs empirically verified in real Linux VMs. 13 KEV-listed. 151 detection rules across auditd/sigma/yara/falco. MITRE ATT&CK and CWE annotated. --explain gives operator briefings.">
 <meta property="og:title" content="SKELETONKEY — Linux LPE corpus, VM-verified">
 <meta property="og:description" content="41 Linux LPE modules; 28 of 36 CVEs empirically verified in real VMs. 151 detection rules. ATT&CK + CWE + KEV annotated.">
 <meta property="og:type" content="website">
@@ -56,7 +56,7 @@
   <div class="container hero-inner">
     <div class="hero-eyebrow">
       <span class="dot dot-pulse"></span>
-      v0.9.8 — released 2026-06-02
+      v0.9.9 — released 2026-06-08
     </div>
     <h1 class="hero-title">
       <span class="display-wordmark">SKELETONKEY</span>
@@ -227,7 +227,7 @@ uid=0(root) gid=0(root)</pre>
         <div class="bento-icon">★</div>
         <h3>CISA KEV prioritized</h3>
         <p>
-          12 of 36 CVEs in the corpus are in CISA's Known Exploited
+          13 of 36 CVEs in the corpus are in CISA's Known Exploited
           Vulnerabilities catalog — actively exploited in the wild.
           Refreshed on demand via <code>tools/refresh-cve-metadata.py</code>.
         </p>
@@ -600,7 +600,7 @@ uid=0(root) gid=0(root)</pre>
       who found the bugs.
     </p>
     <p class="footer-meta">
-      v0.9.8 · MIT · <a href="https://github.com/KaraZajac/SKELETONKEY">github.com/KaraZajac/SKELETONKEY</a>
+      v0.9.9 · MIT · <a href="https://github.com/KaraZajac/SKELETONKEY">github.com/KaraZajac/SKELETONKEY</a>
     </p>
   </div>
 </footer>