🏗️ Extract tome from spire into standalone plugin

Tome is opt-in per project — each project declares its own knowledge
management approach. Spire retains a small knowledge-awareness skill
that explains what tome does and provides a fallback strategy for
projects without it.

- New plugins/tome/ with own manifests, README, all 5 sub-skills
- Spire keeps skills/knowledge/SKILL.md as awareness stub
- Updated all READMEs and marketplace JSONs
- tome: namespace refs now correct (tome is its own plugin)

plugins/tome/skills/navigate/tooling.md

@@ -0,0 +1,12 @@
+---
+status: generated
+source-paths: []
+---
+
+# Detected Tooling
+
+This file is generated by `knowledge.py bootstrap` or `knowledge.py refresh` and
+reflects the toolchains, commands, and scripts detected in the host project.
+
+Run `just tome init` (or `knowledge.py bootstrap`) to populate this file with
+project-specific tooling information.