chore(skill): bump emcli skill version to 0.6.0 (mirror binary)

Mirror the skill metadata version to the binary release and document the
three skill-package touch points in RELEASING.md so they bump together.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

RELEASING.md

@@ -46,11 +46,16 @@ published. If it ever doesn't fit your runner setup, fall back to Option A.
 > public for `skills/emcli/scripts/install.sh` to fetch binaries without a token. A private repo
 > returns 404 to unauthenticated downloads.
 
-## After a release
+## Skill-package version bump (do this in the `chore(release):` commit, before tagging)
 
-The skill installer defaults to `EMCLI_VERSION=v0.4.1`. When you cut a different version, either
-publish under that tag or update the default in `skills/emcli/scripts/install.sh` (and the options
-table in `skills/emcli/AGENTIC-MANUAL.md`).
+The agent skill is versioned in lockstep with the binary. When cutting `vX.Y.Z`, update all three
+of these so the tagged commit is self-consistent, then commit as
+`chore(release): default installer to vX.Y.Z`:
+
+- `skills/emcli/scripts/install.sh` — `VERSION="${EMCLI_VERSION:-vX.Y.Z}"` (and the example asset
+  name in the header comment).
+- `skills/emcli/AGENTIC-MANUAL.md` — the `EMCLI_VERSION` default in the options table.
+- `skills/emcli/SKILL.md` — `metadata.version: "X.Y.Z"` (no `v` prefix; mirrors the binary tag).
 
 ## Versioning
 

skills/emcli/SKILL.md

@@ -4,7 +4,7 @@ description: Read and send email through emcli, a guard-railed CLI gateway that
 compatibility: Requires the emcli binary (run scripts/install.sh to fetch it; needs curl or wget and a Linux/macOS/Windows shell) and the EMCLI_KEY environment variable, which the orchestrator provides. Needs network access to the configured mail server.
 metadata:
   author: steve
-  version: "0.4.0"
+  version: "0.6.0"
   homepage: "https://gitea.dcglab.co.uk/steve/emcli"
 ---