Remove the ai.nimblebrain/context attach and the navigate/startChat actions

[mgoldsborough]

The SDK side of retiring two NimbleBrain host extensions. Companion runtime PR: NimbleBrainInc/nimblebrain (bridge-context-and-action).

• sendMessage(text, context) loses context. The ai.nimblebrain/context key it attached is retired, and the spec's ui/update-model-context carries app state instead. Migration: call updateModelContext({ … }), then sendMessage(text).
• action() supports openApp and openConversation only. startChat duplicated ui/message, and navigate coupled apps to the host's URL layout.
• Types, React hooks, tests, conformance pages, README and docs are updated. The CHANGELOG has an Unreleased Breaking entry with the migration steps.

Breaking: the next release should be a minor bump (0.22.0). Not bumped or tagged here.

Checks: npm run ci passes (561/561), conformance passes (36/36), and the docs build passes.

[mgoldsborough]

QA Review: bridge-context-and-action

Scope: 17 files, +55/−144 · worktree: .claude/worktrees/bridge-context-and-action · reviewed: 34f4c90
Risk: LOW
Why this exists: two NimbleBrain bridge extensions duplicate the spec (ui/message, ui/update-model-context) or tie apps to the host's URL layout; this is the SDK half of retiring them.

Critical (must fix)

None.

Fix in-PR (apply mechanically — no adjudication essay expected)

• r1f1 [CHANGELOG.md:11,15] The Unreleased entry describes host behavior that is true only once the companion runtime PR (Bridge: retire ai.nimblebrain/context; action keeps openApp and openConversation nimblebrain#1278) deploys. On runtime main, web/src/components/AppWithChat.tsx:132 still pastes the chat context into the message as [App Context: …], and web/src/App.tsx:590 still handles startChat. So "the host no longer reads the chat context, so it had stopped reaching the agent" and "It ignores navigate and startChat" are false today. Fix: cut this release after #1278 is deployed, or change the wording to "the NimbleBrain host no longer reads…" with no past-tense claim. Both work. The wording is the smaller change.

Suggestions (optional)

None.

What Looks Good

• It removes code and adds none. The _meta branch, the constant, the hook's second parameter and five tests go, and the one surviving test pins the new wire shape: no _meta on a NimbleBrain host (spec-compliance.test.ts).
• Nothing is left behind. A grep for ai.nimblebrain/context, startChat, navigate actions, CHAT_CONTEXT and two-argument sendMessage across src/, python/, conformance/ and web/ finds only the CHANGELOG history.
• Both migrations already work on the current host. openApp and openConversation are handled at web/src/App.tsx:587,595, and updateModelContext state reaches the prompt as <app-state> (src/prompt/compose.ts:957).
• The vendored Python asset needs no re-vendor. The freshly built dist/synapse-ui.iife.global.js is byte-identical to python/nimblebrain_synapse/_assets/synapse-ui.iife.js.

Body claims

• ✅ npm run ci passes 561/561. Reproduced: 37 files, 561 tests, exit 0.
• ✅ The change is breaking and needs a minor bump. The removed parameter is public, and the CHANGELOG has a ### Breaking entry with migrations.
• ⚠️ Conformance 36/36 and the docs build were not re-run here, because Chromium is not installed in this environment. The conformance change is a single argument.

Next step: the author answers with pr-adjudicate. The Critical bucket is empty, so this PR qualifies for qa-reviewed once r1f1 is applied or contested.

machine record

{
  "kind": "review", "pr": 103, "round": 1,
  "reviewed": "34f4c9006a04b0a8be5165d209df455017a2f1fc", "delta_base": null,
  "risk": "LOW", "stop_gate": "n/a",
  "verdict": "Correct subtraction; one CHANGELOG sentence depends on the runtime companion deploying first",
  "findings": [
    {"id": "r1f1", "bucket": "fix-in-pr", "file": "CHANGELOG.md", "line": 11,
     "claim": "CHANGELOG states the host already ignores the chat context and navigate/startChat; runtime main still reads both",
     "evidence": "reproduced",
     "receipt": "git grep on nimblebrain origin/main: AppWithChat.tsx:132 builds [App Context] prefix; App.tsx:590 startChat handler",
     "preconditions": null,
     "fix": "release after nimblebrain#1278 deploys, or reword without the past-tense claim",
     "scope": "peripheral"}
  ]
}

[mgoldsborough]

Adjudication round 1: one fix applied, nothing contested · fixed at aac0987

Fix in-PR

r1f1 applied in aac0987. The CHANGELOG no longer says the host has already stopped reading the chat context or handling navigate and startChat. That depends on NimbleBrainInc/nimblebrain#1278 deploying.

Verification

CI run 36273293753 is green at aac0987. The change touches only the CHANGELOG.

machine record

{
  "kind": "adjudication", "pr": 103, "round": 1,
  "fixed_at": "aac098791d0d23f31de34a7e67b648ec1ec0362e",
  "verdicts": [
    {"id": "r1f1", "verdict": "valid", "premise": "verified",
     "resolution": "reworded CHANGELOG to drop the shipped-host claims, aac0987"}
  ],
  "ci": "success, run 36273293753"
}