HA: document matter.js 9.0.4 migration fabric loss + commissioning-blocked diagnosis, fix Supervisor API access notes

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

reference/home-assistant.md

@@ -4,8 +4,10 @@
 HA OS at `home.thelonglakelodge.com`, proxied via fritzlab sjc001 remote-proxy
 to `172.24.24.50:8123` (also directly reachable on the lab network). Supervisor
 Observer on `:4357` (read-only health, no auth). API token in `~/.env` as
-`HA_TOKEN` (long-lived user token — has core API + service calls, but NOT the
-`/api/hassio/*` Supervisor proxy → 401). No SSH (`:22` closed, no terminal addon).
+`HA_TOKEN` (long-lived admin token — core API + service calls + Supervisor:
+WS `{"type":"supervisor/api","endpoint":...}` for JSON endpoints, REST
+`/api/hassio/addons/<slug>/logs` for text logs; `/api/error_log` is 404 —
+use WS `system_log/list`). No SSH (`:22` closed, no terminal addon).
 No automatic backups configured (`backup/info` → 0 backups).
 
 Local control via WebSocket: `wss://home.thelonglakelodge.com/api/websocket`,
@@ -68,6 +70,37 @@ Then re-point dashboard climate tiles back to `climate.*_nest` if local control
 is wanted (see dashboard note).
 </matter-outage>
 
+<matter-commissioning-blocked>
+## Matter re-commissioning blocked (2026-07-05)
+
+Addon `core_matter_server` is now 9.0.4 = matter.js server (`matter-server/1.1.7`,
+schema 11) — the 9.0.0 update REPLACED the Python Matter Server; the migration
+left an EMPTY fabric (now `fabric_id: 2`, new compressed id — the pre-June
+fabric `1E5211CA4C7B5275` is gone for good; nodes must be re-commissioned).
+
+Re-commissioning FAILS: server discovers the Nest via mDNS but PASE dials only
+ONE candidate — the Nest's IPv6 link-local (`fe80::…%enp6s18`) — which is
+"Address unreachable"; 3-min timeout, then
+`Commission failed: … (1 of 1 started attempt(s) failed, 1 discovered)`.
+NOT a pairing-code problem (wrong-pin tests fail identically at the same spot).
+
+Facts: HA VM `enp6s18` = 172.24.24.50/24, IPv6 fe80-only (no RA/GUA on vino).
+Nests are WIRELESS on the SAME `vino` network (172.24.24.80-99); UniFi SSID has
+l2_isolation/mcastenhance/proxy_arp all OFF. So either fe80→wireless NDP fails,
+the advertised fe80 belongs to a non-WiFi Nest interface (Thread/BLE MAC
+EUI-64), or matter.js ignores an IPv4 A record candidate.
+matterjs-server has NO documented IPv4/interface knob (only --primary-interface);
+addon passthroughs exist: `matter_server_args`, `matter_server_env_vars`,
+`matter_server_version` (npm pin), `beta`.
+
+Addon `log_level: debug` is SET (revert to info when solved). Next attempt will
+log the full discovery record (all A/AAAA candidates) — that discriminates the
+root cause. A Matter setup code can be generated REMOTELY (Google Home app →
+thermostat → Linked Matter apps & services), then drive
+WS `{"type":"matter/commission","code":"<11-digit>"}` and read
+`/api/hassio/addons/core_matter_server/logs`.
+</matter-commissioning-blocked>
+
 <dashboard>
 ## Main Lovelace (`lovelace` / "Overview", storage mode)