feat(runner): Phase 7I interactive scenario chat over the mock control plane

Adds a chat surface to the Phase 7 browser explorer where the board sends
prompts to a scenario and sees exactly how the mock Paperclip control plane
was used on every turn — the point of the phase is that the activity stays
visible rather than hidden behind the conversation (PAP-16916).

Runtime owns the turn model, so the UI derives nothing:

- `Phase7ChatSession` keeps one long-lived mock core across turns, so the
  state a turn changes is still there for the next one. Turn 0 is the
  control-plane seed (checkout, wake routing, exposure) that exists before
  anyone can type.
- Timeline entries gain a `turn`; the artifact gains `turns[]` with per-turn
  exposure, authorization records, state diff, reconciliation events, counts,
  and a turn-scoped verdict. A new `user_message` kind joins the five
  existing ones.
- `phase7TurnParity` judges a turn on what that turn did. A session-level
  expectation about work nobody has asked for yet would read as a failure of
  turn 1 rather than as work still to come.
- Recording machinery moves to `scenario-execution.ts`, shared with the 7F
  single-shot runner so a scenario reads the same either way.

Two scenarios carry authored multi-turn scripts: `ap-mcp-gate-01` (allowed
turn, then a denied one) and `ix-checkbox-01` (open an interaction, then the
board answers it — a control-plane-owned action with no agent tool, which is
what makes the control plane schedule the continuation wake). Every other
corpus scenario falls back to its 7F plan as one scripted turn.

The surface implements the approved 7I interaction map: turn strips bridging
each turn to its evidence, the six-section activity stream, the mobile
Chat/Activity segments with a deny count chip, reset and scenario-switch
confirmation, and deterministic deep links including a staged streaming hold.
Deviations taken during implementation are recorded in §11a of the map rather
than left for a reviewer to find.

No ACPX implementation, no real control-plane integration, no credential in
the browser: Codex mode stays disabled with a named reason and scripted mode
drives the same in-page mock core offline.

Tests: 30 new runtime/component tests and 18 browser tests; 79 phase-7 unit
and 43 phase-7 browser tests pass. Ten §11 screenshots recorded by
`record:phase7i`, which fails the run on any horizontal page scroll.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

packages/paperclip-runner/docs/tutorials/phase-07i-scenario-chat.md

@@ -0,0 +1,129 @@
+# Phase 7I Tutorial: Chat With the Mock Control Plane
+
+**Time to first success: about 3 minutes.** One command opens a chat where you
+send prompts to a Phase 7 scenario and watch exactly how the mock Paperclip
+control plane was used on every turn. The tutorial runs from the repository
+root. It starts no Paperclip service, contacts no Paperclip control plane, and
+holds no provider credential.
+
+Phase 7I extends the Phase 7 browser surface; it does not integrate the runner
+into Paperclip. Real integration is Phase 8 and requires separate approval. See
+[the future binding boundary reference](../phase-07-future-binding-boundary.md).
+
+## What you need
+
+- Node.js 20 or newer and pnpm 9 or newer. Verified with Node 22.22.2.
+- No Rust toolchain and no network access after `pnpm install`.
+
+Install the package workspace from the repository root:
+
+```sh
+pnpm install --filter @paperclipai/paperclip-runner --lockfile=false --offline --ignore-scripts --dev
+```
+
+## 1. Open the chat (about 1 minute)
+
+```sh
+pnpm --filter @paperclipai/paperclip-runner run demo:phase7
+```
+
+Open <http://127.0.0.1:4183/phase7-explorer/#/chat/ap-mcp-gate-01>.
+
+Before you type anything, the conversation already has content: a **session
+seed** strip reading "Control plane checked out the task and opened the run — no
+agent tool exists for this," and a **Session seed activity** strip counting what
+it did. That is the point of turn 0. Work happened, and no agent tool was
+involved.
+
+The session status chip reads **Idle · seeded**. The right rail — **Activity**
+on desktop, the **Activity** segment on a phone — shows the seed group with its
+exposure decision, state diff, and verdict.
+
+## 2. Run a turn that succeeds
+
+Type into the composer and press Enter:
+
+```
+Where does the MCP tool approval for this task stand?
+```
+
+The turn appends: your message as a right-aligned bubble, two semantic calls
+(`get_task_context`, `list_approvals`) as tool cards with their disposition
+badges, the agent's reply, and a **Turn 1 activity** strip:
+
+```
+Turn 1 activity   ⚙ 2 tools   ⌘ 0 control plane   Δ 0 domains   ✓ Pass
+```
+
+Click the strip. The Activity stream opens turn 1's group with the six evidence
+sections in order — exposed tools, calls and results, authorization, control
+plane, state diff, parity. Nothing changed state, and the diff says so.
+
+## 3. Run a turn that is denied
+
+```
+Raise the approval request yourself and get the tool switched on.
+```
+
+`request_approval` is denied. The denial renders in place on the danger surface
+with the failing operation, the code `policy_denied`, the reason
+`required_claim_missing`, and an explicit line that **no protected state was
+returned**. The turn strip counts it (`✕ 1 denied`), and on mobile the Activity
+segment carries a `· 1 deny` chip so you can see it without opening the segment.
+
+The session status still reads **Scripted · deterministic** and the session
+parity still passes. A denial is a correct outcome, not a broken session — this
+run simply does not hold `governance:approvals:request`. Open the turn's
+**Authorization** section to see the claims considered and the missing one.
+
+## 4. See control-plane-owned work with no agent tool
+
+Open <http://127.0.0.1:4183/phase7-explorer/#/chat/ix-checkbox-01?replay=fake>.
+`replay=fake` plays the recorded three-turn conversation.
+
+Turn 2 opens a checkbox interaction. Turn 3 is the board answering it — and
+that answer is performed by the control plane, not by a tool:
+
+```
+⌘ Control plane recorded the board's answer and scheduled the continuation
+  wake — no agent tool exists for this.
+```
+
+Open turn 3's **State diff** section. The `interactions` domain shows
+`status: pending → answered`, the unchanged domains collapse to one line, and a
+**Control plane** badged row records `wake.scheduled`. The wake is scheduled by
+reconciliation; the agent never asked for it.
+
+## 5. Reset and replay
+
+**Reset session** asks first, because it discards mutable mock state. Accept it
+and the transcript returns to the seeded turn 0 — no turns, no denials, a clean
+diff. Switching scenario from the rail mid-session asks the same question, since
+two scenarios never share mock state.
+
+**Replay scripted session** plays the remaining recorded turns and needs no
+confirmation: it reproduces an identical timeline.
+
+## 6. Run the tests and record the evidence
+
+```sh
+pnpm --filter @paperclipai/paperclip-runner run test:phase7
+pnpm --filter @paperclipai/paperclip-runner run test:browser:phase7
+pnpm --filter @paperclipai/paperclip-runner run record:phase7i
+```
+
+The first covers the session data contract and the chat components, the second
+drives the surface in a real browser at both viewports, and the third writes the
+ten acceptance screenshots to `knowledge/evidence/phase-07/` — failing if any
+route scrolls horizontally.
+
+## What this does not do
+
+- No ACPX implementation and no real control-plane integration.
+- No provider credential in the browser. **Codex (bounded)** stays disabled with
+  a named reason unless the local provider relay is running; **Scripted
+  (deterministic)** drives the same mock core offline.
+- Nothing you type is persisted. A reload drops an unsent draft, which is the
+  accepted trade against storing conversation content.
+
+Reference: [Phase 7I scenario chat](../phase-07i-scenario-chat.md).