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/skills/echo-save/SKILL.md

@@ -0,0 +1,30 @@
+---
+name: echo-save
+description: Save to ECHO memory — route content to its canonical home (search-first, idempotent)
+argument-hint: "[what to remember]"
+allowed-tools: Bash(python3 *echo.py*), Bash(python *echo.py*), Bash(py -3 *echo.py*), Bash(ls /sessions/*)
+---
+
+Use the **echo-memory** skill to persist this to the ECHO vault:
+
+> $ARGUMENTS
+
+Prefer the one-call **`capture`** — it routes (via the entity index), derives the canonical path, stamps complete frontmatter (kind-default `status`, the kind seeded into `tags`), indexes, auto-links mentioned entities, and writes the Agent-Log line. Pick the `--kind` from the content (`person, company, concept, reference, meeting, project, area, semantic, episodic, working, skill, decision`); add `--tags` when obvious; use `--inbox` only when the home is genuinely unknown. Write multi-line bodies to a file with the Write tool (cross-platform, no heredoc) — updates to an existing entity preserve the whole body, so don't pre-trim it.
+
+```bash
+ECHO="${CLAUDE_PLUGIN_ROOT}/skills/echo-memory/scripts/echo.py"   # run with: python3 "$ECHO" ... (Windows: python / py -3)
+[ -f "$ECHO" ] || ECHO=$(ls /sessions/*/mnt/.remote-plugins/*/skills/echo-memory/scripts/echo.py 2>/dev/null | head -1)   # CoWork sandbox fallback
+python3 "$ECHO" capture "<title>" <bodyfile> --kind <kind> [--aliases a,b] [--tags t1,t2] [--source p1,p2]
+python3 "$ECHO" capture "<title>" --inbox     # unknown home -> idempotent inbox line
+```
+
+**If capture exits `76` (duplicate gate):** the title strongly resembles an existing entity — do NOT retry blindly. Show the operator the printed candidates and either update the existing note (`capture ... --merge-into <slug>`) or, only after they confirm it's genuinely distinct, re-run with `--force`.
+
+Drop to the low-level verbs only for shapes `capture` doesn't model (a project `## Status` replace, an ADR mirror, a daily-note edit):
+
+```bash
+python3 "$ECHO" put   <routed/path>.md <bodyfile>                       # create/overwrite (verifies)
+python3 "$ECHO" patch <path>.md append heading "<H1::Sub>" <bodyfile>   # targeted append
+```
+
+Write in third person about the vault owner; never put `[[wikilinks]]` in frontmatter. `capture` handles `agent_written`, `source_notes`, indexing, and linking for you; if you write by hand, `resolve "<title>"` first to avoid duplicates and `bump` `updated:` only on substantive changes.