slag 2.6.0 — wave 5: MCP tools + sleep guard

MCP stdio client. An [mcp] table in ~/.config/slag/config.toml adds Model Context Protocol servers, one command per line:

[mcp]
filesystem = "npx -y @modelcontextprotocol/server-filesystem /tmp"
github = "gh-mcp --stdio"

slag spawns each server at forge start and hands the smith every tool it advertises, named mcp__<server>__<tool>, beside the built-in eight. Recipes gate on those names through requires_tools unchanged. A server that will not start is named in a warning and skipped, so the forge runs on the natives. stdio transport only: no HTTP, SSE, or OAuth.

Sleep guard. A leading sleep N with N >= 2 in the bash tool is refused with the remedy named: raise timeout, use the checker's own retry, or poll in an until loop. Float durations, sub-2s pacing, sleep 5 &, and sleeps inside pipelines, loops, and subshells still pass.

Release script. dist-local/publish-release.sh reads the version from Cargo.toml, verifies the committed assets against their checksums, and refuses to publish from a dirty tree or over an existing tag.

522 tests.