feat(v0.6): namespace all 14 master slash commands under /master-<slug> prefix

Slash command discoverability cleanup. Claude Code users typically have
50+ skills installed; bare-word commands like /atisha and /zhiyi got
scattered across the /-completion list. v0.6 prefixes all 14 master
slash commands with master- so they cluster under /m<tab> and clearly
signal "this is a Master-skill master skill".

Scope of rename
---------------
* Slash commands: /zhiyi → /master-zhiyi, /huineng → /master-huineng,
  ... all 14 affected.
* Directory layout: prebuilt/<slug>/ → prebuilt/master-<slug>/ for all
  14 masters (git mv preserves history).
* Frontmatter: each prebuilt/master-<slug>/SKILL.md updates `name:` to
  master-<slug>.
* compare-masters and create-master meta-skills are intentionally
  unchanged — they're already prefixed by their nature, and
  /master-compare-masters would be doublespeak.

Decoupling: fojin.app/chat is NOT affected
------------------------------------------
The fojin web frontend's master dropdown uses bare slug IDs (atisha,
huineng, ...) and is already grouped under "法师模式" in its UI. Backend
master_profiles.py keeps `id="atisha"` etc. unchanged. No fojin-side
migration required. The two surfaces (Claude Code slash + fojin
dropdown) are now formally decoupled by design, not coincidence.

Compatibility
-------------
* NPX installer accepts both forms: `npx master-skill install zhiyi`
  (short) and `install master-zhiyi` (full) both resolve to the same
  prebuilt/master-zhiyi/ source. Install destination is always
  ~/.claude/skills/master-<slug>/. Backward-compatible uninstall
  handles legacy non-prefixed installs (~/.claude/skills/zhiyi/).
* The cli.mjs already used `master-${name}` for install destinations
  (since v0.3 NPX installer was added), so existing v0.4/v0.5 NPX
  users were already getting the prefix in skills/ — only the source
  prebuilt/ layout and slash commands change in v0.6.

Files updated
-------------
* 14 directories renamed (28 files moved, 0 content changes).
* 14 SKILL.md frontmatter `name:` fields.
* prebuilt/compare/SKILL.md: 43 slug references updated to prefixed form.
* bin/cli.mjs: resolveMasterDir helper accepts both short and full;
  cmdInstall and cmdUninstall handle legacy paths.
* .github/workflows/validate-and-test.yml: fidelity-smoke MASTERS
  rotation array updated to all 14 prefixed names (was 8 hardcoded
  汉传 only — now properly rotates across the full set).
* scripts/{validate,cite,query,test-fidelity}.py: --master arg help
  text examples.
* README.md + README_EN.md: situational guidance table, install
  snippets, master cards. New v0.6 release banner.
* SKILL.md (project-level) preset list with new slash names.
* ETHICS.md Tier table slug references (4).
* All plugin manifests bumped 0.5.0 → 0.6.0 with description noting
  the /master-<slug> invocation pattern.
* CHANGELOG.md: [0.6.0] section with breaking-change notice and
  migration commands for existing NPX users.

Validation
----------
* python scripts/validate.py --strict           ✓ 15 masters pass
* python scripts/validate-fidelity.py           ✓ all valid
* python scripts/test-fidelity.py --all --dry-run  ✓
* pytest tests/                                  ✓ 31 passed, 6 skipped
* node bin/cli.mjs list                          ✓ shows all 14 with
                                                   master- prefix
* node bin/cli.mjs install zhiyi                 ✓ resolves to
                                                   prebuilt/master-zhiyi/
* node bin/cli.mjs install master-zhiyi          ✓ resolves to same

Migration for existing v0.4/v0.5 users
--------------------------------------
    npx master-skill@0.5 uninstall zhiyi huineng xuanzang ...
    # OR: rm -rf ~/.claude/skills/{zhiyi,huineng,...}
    npx master-skill@latest install --all

Then start a new Claude Code session; the new slash commands are
/master-zhiyi, /master-huineng, etc.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

bin/cli.mjs

@@ -66,15 +66,26 @@ function cmdList() {
   console.log();
 }
 
+// Resolve a master directory accepting both short ("zhiyi") and full
+// ("master-zhiyi") forms. Returns the absolute prebuilt/<dir> path or null.
+function resolveMasterDir(input) {
+  const candidates = [
+    path.join(PREBUILT, input),                  // exact: master-zhiyi
+    path.join(PREBUILT, `master-${input}`),      // short: zhiyi → master-zhiyi
+  ];
+  return candidates.find((p) => fs.existsSync(p)) || null;
+}
+
 function cmdInstall(names) {
   fs.mkdirSync(SKILLS_DIR, { recursive: true });
   for (const name of names) {
-    const src = path.join(PREBUILT, name);
-    if (!fs.existsSync(src)) {
-      console.log(`  ✗ ${name} — not found in prebuilt/`);
+    const src = resolveMasterDir(name);
+    if (!src) {
+      console.log(`  ✗ ${name} — not found in prebuilt/ (tried "${name}" and "master-${name}")`);
       continue;
     }
-    const dest = path.join(SKILLS_DIR, `master-${name}`);
+    const dirName = path.basename(src);          // master-zhiyi
+    const dest = path.join(SKILLS_DIR, dirName);
     cpR(src, dest);
     console.log(`  ✓ ${name} → ${dest}`);
   }
@@ -82,19 +93,25 @@ function cmdInstall(names) {
 
 function cmdUninstall(names) {
   for (const name of names) {
-    const dest = path.join(SKILLS_DIR, `master-${name}`);
-    if (!fs.existsSync(dest)) {
+    // Try both prefixed and bare directory names for backward compatibility
+    // with any pre-v0.6 installs that may still sit at ~/.claude/skills/<slug>/.
+    const candidates = [
+      path.join(SKILLS_DIR, name),               // exact: master-zhiyi
+      path.join(SKILLS_DIR, `master-${name}`),   // short: zhiyi → master-zhiyi
+    ];
+    const dest = candidates.find((p) => fs.existsSync(p));
+    if (!dest) {
       console.log(`  ✗ ${name} — not installed`);
       continue;
     }
     fs.rmSync(dest, { recursive: true, force: true });
-    console.log(`  ✓ ${name} removed`);
+    console.log(`  ✓ ${name} removed (${dest})`);
   }
 }
 
 function showHelp() {
   console.log(`
-master-skill — Chinese Buddhist Master AI Skills installer
+master-skill — Buddhist Master AI Skills installer (v0.6+)
 
 Usage:
   master-skill install <name...>   Install masters to ~/.claude/skills/
@@ -103,8 +120,12 @@ Usage:
   master-skill uninstall <name...> Remove installed masters
   master-skill --help              Show this help
 
+Names accept both short (zhiyi) and full (master-zhiyi) forms.
+Slash commands are always /master-<slug> (e.g. /master-zhiyi).
+
 Examples:
   npx master-skill install zhiyi fazang
+  npx master-skill install master-milarepa master-tsongkhapa
   npx master-skill install --all
   npx master-skill list
   npx master-skill uninstall zhiyi