chore: retire docs/specs and docs/plans as committed artifacts

Per-cycle specs/plans are step-scoped: every file maps to already-shipped
code, their snippets drift hard against current APIs (InputSpec->PortSpec,
Sim->Harness, schema() removed, C16 zero-dep reversed, ascii-dag retired),
and a stale spec read as an API reference misleads agents into non-compiling
code. No durable knowledge lost — rationale lives in the ledger + code
rustdoc, history in git + the tracker.

- gitignore docs/specs/ and docs/plans/
- delete all 117 existing specs/plans (recoverable via git history)
- CLAUDE.md: specs/plans are local-only ephemeral artifacts

CLAUDE.md

@@ -7,8 +7,12 @@ freeze a validated strategy into a standalone bot with a broker connection.
 
 This file is the project sittenkodex. It imports the universal discipline from
 `~/dev/skills/templates/CLAUDE.md.fragment` and adds aura's domain invariants.
-The full architecture lives in the design ledger (`docs/design/`) and the specs
-(`docs/specs/`), not here.
+The full architecture lives in the design ledger (`docs/design/`), not here.
+Per-cycle specs (`docs/specs/`) and plans (`docs/plans/`) are local-only,
+ephemeral working artifacts — git-ignored, valid only for the cycle that
+produces them. Durable rationale is lifted to the ledger; a spec/plan is never
+treated as a live API reference (its code snippets drift the moment the code
+moves). The canonical record of past cycles is the ledger plus the git history.
 
 ## Roles