docs: name the ecosystem, correct the latency, drop the stale handoff

Three documentation changes and one deletion.

CLAUDE.md and AGENTS.md gain the Nexus/Praxis/Hexis sections that were written
last session and never committed: what each service owns, where Maven's client
for it lives, and the rules that are not negotiable.

The p50 latency figure was wrong in two files. CLAUDE.md said the cascade costs
2.7s and that the LLM router is 90x slower than the classifier. Both come from
the bakeoff table, where the number is contention on a shared llama-server, not
the model. ROUTING-EVAL-31-07-2026.md line 61 says so and measures the router at
p50 825ms / p95 1.2s / max 3.0s. Corrected in CLAUDE.md, and the bakeoff table
now carries a header pointing at the routing eval for absolute latency. Latency
work was about to be planned off a number that was never real.

HANDOFF.md is deleted. It described work sitting on fix/integrated waiting for a
fast-forward onto overnight/eco-versioned-traces. Neither is true: master
contains that tip plus 22 commits, and both branch pointers are stale. The three
live defects it recorded move to PLAN-DETERMINISM-02-08-2026.md, which is now
the only planning document.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BFaeSbLMEVG5ey8tejU3y2

CLAUDE.md

@@ -68,6 +68,45 @@ Daemons are wired socket-to-socket, not linked. `internal/ipc` is the client/ser
 protocol; the config in `deploy/mavend.json` (with `${VAR}` env expansion from gitignored
 `deploy/telegram.env`) sets socket paths, model paths, and the phraser/embedder blocks.
 
+## The ecosystem: Nexus, Praxis, Hexis
+
+Maven is one of four services. It owns conversation and personal memory. It does not
+own identity, operational state, or execution. Full contract in
+`MAVEN_ECOSYSTEM_ARCHITECTURE.md`.
+
+```text
+Nexus identifies.  Praxis observes.  Hexis acts.  Maven understands and coordinates.
+```
+
+| Service | Owns | Maven's client | Configured at |
+|---|---|---|---|
+| **Nexus** | Canonical entity ids, names, aliases, relationships. Projects, services, devices, people, pets, places. | `nexusClient` in `cmd/mavend/ecosystem.go`, `POST /api/v1/resolve` | `nexus.url` (`http://nexus:9740`) |
+| **Praxis** | Operational attention and item lifecycle. What needs looking at, what changed, what is still unresolved. | `praxisClient`, the HTTP tools API under `/api/v1/tools/` | `praxis.url` (`http://praxis:8989`) |
+| **Hexis** | The capability registry and the only path to executing anything. | vendored `github.com/kami/hexis/pkg/client` | `hexis.url` (`http://hexis:9741`) |
+
+All three are `nil` unless configured, and every one of them degrades on its own.
+An outage means a named gap in the answer, never a broken turn and never a guess.
+
+Rules that are not negotiable:
+
+- **No component reads another component's database.** Praxis attention comes over
+  HTTP, never from its SQLite file.
+- **Identity lives in Nexus.** Do not invent a local fact key for something Nexus
+  resolves. `actionFact` already sets `Subject`, and `cmd/mavend/factenrichment.go`
+  resolves it in the background against Nexus.
+- **Free text never reaches a mutating Hexis call.** Resolve to a canonical entity id
+  first. Ambiguous resolution asks the owner, it does not pick.
+- **LLM output is not authorization.** Confirmation binds capability id, target
+  entity, arguments, requester and expiry. See `cmd/mavend/confirm.go`.
+- **Praxis lifecycle words mean different things.** Surfaced is not acknowledged,
+  acknowledged is not resolved, execution success is not recovery. Reading an item
+  aloud calls `Surface`, never `Acknowledge`.
+- **No automatic attention-to-action path.** Digestion may summarise Praxis. It may
+  not call Hexis.
+
+Every cross-service call carries a correlation id minted once per action
+(`withCorrelationID`), a contract version header, and `X-Requested-By: maven`.
+
 ## Routing — read this before touching the router
 
 `internal/router/` has TWO layered engines. **The LLM router is now the default and it is
@@ -90,8 +129,11 @@ fallback. Any LLM error falls through to the classifier so a turn never breaks o
 
 Measured on the 77-case RU fixture (`MODEL-BAKEOFF-31-07-2026.md`): the classifier scores
 36.8% full accuracy at p50 31ms; Qwen3-1.7B scores 67.5% intent-only / 72.7% through the
-cascade at p50 ≈2.7s. Accuracy roughly doubled, latency is ~90× worse, and that trade was
-accepted deliberately. `Confidence: 1.0` used to be hardcoded in `llmrouter.go`, so the LLM
+cascade at p50 ≈825ms. Accuracy roughly doubled, latency is ~27× worse, and that trade was
+accepted deliberately. **The ≈2.7s figure that stood here until 2026-08-02 was contention,
+not the model.** See `ROUTING-EVAL-31-07-2026.md` line 61, which measures the LLM router at
+p50 825ms / p95 1.2s / max 3.0s and the full cascade at p50 0.80-1.04s. Do not plan latency
+work off the bakeoff table. `Confidence: 1.0` used to be hardcoded in `llmrouter.go`, so the LLM
 path could never ask for clarification (6/6 refusal cases missed on the fixture) — Vikunja
 #359. Fixed 31-07-2026 with structural signal (single-token utterance, keyless fact, act with
 no allowlisted fn) feeding the same stage-3 gate the classifier path already had — see