chore: drop restated spec/plan lifecycle from CLAUDE.md; git-ignore docs specs/plans

The spec/plan lifecycle is a fixed plugin convention (skills/docs/conventions.md, sections File layout + Lifecycle). Restating it here is a drift vector: it had already gone stale (said git-tracked while the plugin moved to git-ignored on Jul 2). Remove the restated paragraph and enforce the git-ignored model with a project-local docs/.gitignore.

CLAUDE.md

@@ -8,12 +8,6 @@ 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/`), not here.
-Per-cycle specs (`docs/specs/`) and plans (`docs/plans/`) are ephemeral working
-artifacts, kept git-tracked — committed while their cycle is live and removed
-(`git rm`) at cycle close, 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
 

docs/.gitignore

@@ -0,0 +1,5 @@
+# Per-cycle working artifacts — git-ignored, never committed.
+# Present on disk for the active cycle, rm'd at cycle close.
+# See ~/dev/skills/docs/conventions.md § Lifecycle.
+specs/
+plans/