Reserve agentminds_io extension namespace

AgentMinds operates a cross-site agent intelligence pool. This
namespace reserves the extension fields needed to express
cross-site pattern lifecycle (confidence, seen count, last
verified, volatility class) — primitives that have no canonical
OASF equivalent today.

Per ARP §7 reorientation clause, if a future OASF version absorbs
these primitives, AgentMinds will defer to the canonical schema.

Signed-off-by: UzunGridera <fabrecamimarlik@gmail.com>

Author: UzunGridera

schema/extensions/agentminds_io/README.md

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+# `agentminds_io` extension namespace
+
+**Owner:** AgentMinds — https://agentminds.dev
+**Contact:** fabrecamimarlik@gmail.com
+**Reserved:** 2026-04-27
+**License:** CC-BY-4.0 (extension definitions); MIT (reference code)
+**Spec:** https://github.com/agentmindsdev/profile
+
+## Purpose
+
+Reserve the `agentminds_io` extension namespace for AgentMinds-
+specific OASF record fields that have no canonical equivalent in
+the upstream OASF schema. AgentMinds operates a cross-site agent
+intelligence pool; the fields below describe state that only has
+meaning across organisations.
+
+## Initial extension fields
+
+| Field | Type | Description |
+|---|---|---|
+| `agentminds_io.pattern.id` | string | Cross-site pattern identifier (lowercase hex SHA-256, 64 chars) |
+| `agentminds_io.pattern.fingerprint` | string | Alias of `.id` for Sentry-style readers |
+| `agentminds_io.pattern.confidence` | float [0,1] | Beta-Bernoulli posterior confidence |
+| `agentminds_io.pattern.cross_site_seen_count` | int | Distinct sites that observed this pattern |
+| `agentminds_io.pattern.last_verified` | RFC3339 | Last network-wide confirmation timestamp |
+| `agentminds_io.pattern.volatility_class` | enum (`stable`/`evolving`/`decaying`) | Drift detection signal |
+| `agentminds_io.report.profile_version` | semver | ARP version this report follows |
+
+## Reorientation clause
+
+Per the AgentMinds Reporting Profile (ARP) §7, if a future canonical
+OASF version introduces a cross-site pool concept that absorbs these
+fields, AgentMinds will defer to the canonical definitions. This
+extension namespace becomes a backwards-compatible alias.
+
+## Reference
+
+- AgentMinds Reporting Profile (ARP):
+  https://github.com/agentmindsdev/profile
+- Reference implementation:
+  https://github.com/agentmindsdev/agentminds (closed-source;
+  excerpts available on request)