docs(shared): conform bygg-energi-mikro to the shared OKF spec (okf_version 0.1)

Cross-coordination with the marketplace OKF convention
(ktg-plugin-marketplace/catalog/docs/okf-second-brain/spec.md v0.1). The
bundle already passed the shared acceptance gate; the one spec MUST-gap was the
root index okf_version marker (spec §3). Added it.

Verified: `node catalog/scripts/okf-check.mjs <bundle>` -> okf_version: 0.1,
"OK: valid OKF bundle", exit 0. Bundle-consuming tests green (14).

Scope note (honest): portfolio-optimiser uses OKF for framework per-project
runtime knowledge, NOT the user "second brain" the marketplace convention is
scoped to. Same FORM (now conformant + gate-clean), different SCOPE. Two
recommended `resource` warnings left deliberately (spec §4 sanctions omission;
no canonical URI to assert without fabricating). The index.md frontmatter is a
known deviation from spec §6 (reserved index = no frontmatter) kept for now
because okf.py navigation classifies the index by its type.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MHR8iKxJRxDiDfNw8HZmWE

shared/examples/bygg-energi-mikro/index.md

@@ -1,5 +1,6 @@
 ---
 type: index
+okf_version: 0.1
 title: "Bygg-energi mikro-eksempel — kontorbygg, LED-retrofit"
 description: "Minimal OKF-bundle for ett kontorbygg med ett energieffektiviseringstiltak (LED-belysningsretrofit). Utviklings-fixture for den agentiske loopen: kontekst → hypotese → deterministisk validering → ekspert-dom → læring."
 tags: [energieffektivisering, M&V, IPMVP, mikro-eksempel, fixture]