docs(readme): document /compose-solution meta-composer and feedback loop

Adds a Meta-composer section between Cross-tool bridges and License. The
section explains the one-paragraph intake, links to the 7-phase pipeline,
shows a hook-creation example that routes to /escalate-recurrence, and
emphasizes the Phase 6 block-augmentation feedback loop — the kit gets
smarter with every invocation, with before/after _blocks/ count reported
per session.

README.md

@@ -143,6 +143,16 @@ KeiSeiKit ships 11 verified tool-bridge templates under `_bridges/`. Render them
 
 All paths are idempotent: existing bridge files in the project are skipped, never overwritten. See `_bridges/README.md` for the full template→output-path table.
 
+## Meta-composer
+
+`/compose-solution` is the meta-creator: tell it what you want to solve in one free-text paragraph, it decomposes the task, greps existing blocks / skills / manifests / bridges for prior art, proposes a minimal math-first architecture, and assembles the right artefact — agent, skill, hook, rule, or block. Every decision except the intake is a click (option-picker), never free-text.
+
+Example: "I want a hook that blocks `rm -rf ~/` in any Bash call" → Phase 2 decomposes into (pattern-match, severity, event, wiki entry) → Phase 3 greps `hooks/` and `_blocks/` for prior art → Phase 5 proposes `hook = PreToolUse:Bash + pattern + exit 2` → Phase 7 hands off to `/escalate-recurrence` with severity and event pre-filled.
+
+Phase 6 is the feedback loop: when a component has no prior art, the skill drafts a new `_blocks/<slug>.md` and — on your click — persists it. Next time `/compose-solution` (or `/new-agent`) runs, that block is discoverable. Every session leaves the kit a little smarter; the report prints `_blocks/` count before → after so the growth is visible.
+
+See `skills/compose-solution/SKILL.md` and its phase files (`phase-1-intake.md` through `phase-7-assemble.md`) for the full 7-phase pipeline.
+
 ## License
 
 MIT. See `LICENSE` in this directory.