docs: remove stale 'not for external distribution' note from BLUEPRINT §13

v0.1.0 has shipped. The closing internal-only annotation is no longer accurate.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: MacFall7

BLUEPRINT.md

@@ -347,7 +347,3 @@ No marketing copy. No emoji. No "Get started in 30 seconds." This is a governanc
   - Spine Lite v0.1.0 receipt format is treated as the canonical v1.0.0 receipt schema for cross-language interop
   - MIT license matches Spine Lite licensing posture (not BSL like Governed Swarm — this is the wedge product, not the moat product)
   - The `tests/M87.Spine.Tests/fixtures/spine_lite_receipt_sample.jsonl` fixture is committed manually before the build session opens, NOT generated by Claude Code
-
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-*M87 Studio LLC. Internal architecture reference. Not for external distribution until v0.1.0 ships.*