1.6.0 — skills-format migration, lint retired-path fix, plugin.json completeness

Skills migration: each of the eight slash commands gains a skills/<name>/SKILL.md
twin (same invocation name, byte-identical body). Per-skill allowed-tools
pre-authorize the resolved python3/python/py -3 invocations + the CoWork ls
fallback probe; disable-model-invocation: true makes /echo-sweep and /echo-triage
operator-only. Docs-confirmed: a same-name skill takes precedence over the legacy
command, so commands/ coexists until its scheduled 2.0 deletion. The $ECHO
path-resolution dedupe is resolved as not-supported (skill dirs are
self-contained; no cross-skill snippet sharing).

Lint fix: vault_lint.py checks retired patterns BEFORE routes, so a seed README
inside a retired tree (archive/...) flags retired-path instead of being absolved
by the permissive leaf-readme route. New end-to-end regression test seeds
archive/notes/README.md (fails pre-fix, passes now).

plugin.json: version 1.6.0, homepage + repository -> git.alwisp.com/jason/echo.

All suites green: 25/25 client unit tests (incl. routing-sync guard), feature,
reflect, offline-queue, PATCH-semantics. Artifact rebuilt (87 entries, both
formats); pointer refreshed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

echo-memory.plugin.src/.claude-plugin/plugin.json

@@ -1,6 +1,8 @@
 {
   "name": "echo-memory",
-  "version": "1.5.1",
+  "version": "1.6.0",
+  "homepage": "https://git.alwisp.com/jason/echo",
+  "repository": "https://git.alwisp.com/jason/echo",
   "description": "Persistent memory via the ECHO Obsidian vault over the Obsidian Local REST API. Cross-platform Python client: one-call capture/resolve/recall/link/triage over an entity index, hybrid BM25 + graph recall spanning entities + sessions/journal (recency/status-aware), a pre-write duplicate gate, complete-frontmatter capture, session hooks that self-fire load/reflect, offline write-ahead queue, lock-guarded concurrency, linter-enforced routing, and /echo-* commands.",
   "author": {
     "name": "Jason Stedwell"