Transparency policy: public read-only, revenue/expense stays LLC-private (#826)

https://projects.knownelement.com/issues/826#note-15

README.md

@@ -31,3 +31,18 @@ flowchart LR
 Work tracking: [Redmine #826](https://projects.knownelement.com/issues/826)
 
 > **Docs live on Discourse — this repo is the executable source of truth.**
+
+## 🔓 Transparency policy (org standard)
+
+The site and this repo are **public read-only** — ultra-open and transparent
+by default. The one carve-out: **revenue and expense detail is private
+(LLC members only)** and is never published here. Practically:
+
+- Public: performance/audit data, benchmarks, risk intelligence,
+  architecture and decision reports.
+- Never published: SITER-Solar financials (project cost, billing history,
+  ROI detail), KillBill revenue data, contract rates.
+- `grav-publish.sh` publishes from an explicit whitelist only — anything
+  new must be added deliberately, not swept in by default.
+- The Grav local admin account is disabled; publishing is exclusively
+  git-based through this repo.