Real-client linked launch proof

Place linked-launch-top-level.e2e.ts in scripts/scenarios and use the accompanying scripts/e2e.config.ts. The remaining scenario helpers are the repository's existing t3.ts, shell.ts, and start-app.ts.

Install dependencies with vp i in both application checkouts. Run the same driver once per commit, with a different fresh T3_PROOF_HOME and output directory:

```sh
T3CODE_DEV_SEED=0 \
T3_PROOF_SCRATCH="$PROOF_SCRATCH" \
T3_SCENARIO_APP_DIR="$PROOF_APP_DIR" \
T3_PROOF_HOME="$PROOF_STATE_HOME" \
vp run scenarios scenarios/linked-launch-top-level.e2e.ts --target web --output .e2e/proof-side
```

PROOF_SCRATCH is an existing private scratch directory. PROOF_APP_DIR is the application checkout to exercise; PROOF_STATE_HOME is a fresh, checkout-local data directory. Run from the checkout holding the driver and config. Output must be inside its scripts directory.

The driver starts two real servers running that commit, enables Linked environments, creates synthetic projects through t3.project and a remote replay thread through t3.thread, links A to B through the CLI, and connects both to Chromium through Connections. A stock replay agent runs through a proxy that retains its actual MCP credential and holds the coordinator turn open. The driver sends real authenticated MCP calls with that thread scope, without inserting thread metadata into the database.

The launch supplies B's environmentId and projectId, a replay selection, message, fresh request namespace, and delegatedFrom identifying the active coordinator on A. The control uses orchestrator_capabilities then delegate_task to B. The browser opens the standalone launch, returns to its parent, and expands Previous agents. Both captures require two identical PNGs at least 500 ms apart. Browser: Chromium, 1280×800, light theme, reduced motion.

Base: the visibility assertion fails because the standalone row is absent. Head: both the standalone row and genuine delegated Lineage entry are visible. Recordings are trimmed to the same launched-conversation → parent → expanded-Lineage interaction, excluding pairing and teardown. No production source changes were made.

AI-assisted; verified with the tests and tools listed above.