chore(commands): rewrite /rune:* slash commands for v0.4 Go binary

[couragehong]

Sweeps v0.3 Python-era leftovers from the 9 commands/claude/*.md files the plugin manifest exposes as user-facing slash commands. The Python MCP server, .venv, install.sh, and mcp__plugin_rune_envector__ tool prefix are all gone in v0.4 — keeping their references in the docs sent users to dead paths.

Changes per file

activate.md (largest rewrite):

• drop steps 4 (.venv check + auto-install.sh), 5a (Python TCP probe
  • Python token validation via VaultClient import), 5b (.venv sanity check)
• drop "restart Claude Code as fallback" — Task Rune Benchmark Framework including: #28 (fix(lifecycle): re-spawn boot loop on dormant reload #117) made Manager.Retrigger re-spawn the boot loop on dormant, so reload is sufficient
• reshape Steps 5–8 around mcp__envector__{reload_pipelines, diagnostics, vault_status} — the MCP tools the v0.4 server already exposes for this purpose
• allowed-tools narrowed accordingly (no python3, no scripts/, no curl, no find)

capture.md, recall.md, delete.md, history.md:

• mcp__plugin_rune_envector__* → mcp__envector__* (server name in .claude-plugin/plugin.json is "envector"; the "plugin_rune_" prefix is from an earlier plugin layout that no longer exists)
• drop Bash(python3:*) from allowed-tools (capture/recall)

reset.md:

• drop Bash(python3:*) from allowed-tools

deactivate.md:

• drop "MCP pipelines will remain live until session restart" — same Task Rune Benchmark Framework including: #28 reason as activate.md

configure.md:

• drop the "Known issue: ReloadPipelines doesn't yet re-spawn RunBootLoop ... restart Claude Code" block (Task Rune Benchmark Framework including: #28 fix landed)

status.md:

• mcp__rune__diagnostics / mcp__rune__vault_status → mcp__envector__*
• drop the Infrastructure section's "Python venv" line — diagnostics already covers what's actually meaningful in v0.4
• drop Bash(python3:) and Bash(scripts/) from allowed-tools