fix(agent-author): require plugin version bump after agent changes

## Why
Same gap as skill-author: no instruction to bump the plugin version after
creating or modifying an agent inside a plugin.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/kyberforge/skills/agent-author/SKILL.md

@@ -26,6 +26,7 @@ metadata:
 
 ## Gotchas
 
+- If the agent lives inside a plugin (its path contains a `plugin.json`), bump the plugin version after every change — in both `plugin.json` and `.claude-plugin/plugin.json` in the same edit pass. Convention: new agent → minor bump; improvement or fix → patch bump. Plugin consumers compare this version to detect updates; skipping it makes the change invisible.
 - Plugin agents silently ignore `hooks`, `mcpServers`, and `permissionMode` — these fields have no effect and produce no warning. They only work in `.claude/agents/` or `~/.claude/agents/`.
 - `AskUserQuestion`, `EnterPlanMode`, `ExitPlanMode`, and `ScheduleWakeup` are never available to any subagent regardless of the `tools` field.
 - Duplicate `name` values in the same scope: Claude Code silently discards one without warning. Always verify uniqueness before shipping.
@@ -145,6 +146,8 @@ If no research sources are in context, delete `agents/sources.md`.
 - [ ] No Claude Code-only fields (`maxTurns`, `isolation`, `memory`, `permissionMode`, `effort`)
 - [ ] System prompt body present and non-empty
 
+If the destination is inside a plugin directory, apply a **minor bump** to the `version` field in both `plugin.json` and `.claude-plugin/plugin.json` at the plugin root in the same edit pass (e.g. `1.0.4` → `1.1.0`).
+
 ## Improving an existing agent
 
 ### Step 1 — Verify inputs
@@ -179,3 +182,5 @@ Edit any file the signals point to. Generalize the fix — find the underlying g
 ### Step 5 — Validate and close
 
 Re-run the validation checklist from the create flow's Step 5 on any edited file.
+
+If the agent lives inside a plugin directory, apply a **patch bump** to the `version` field in both `plugin.json` and `.claude-plugin/plugin.json` at the plugin root in the same edit pass (e.g. `1.0.4` → `1.0.5`).