Add Browser Collector Enrollment Primitive

Why

A trusted owner agent (Daisy/Simon-style) can already initiate a local-collector connection through POST /v1/owner/connections/intents, but a browser-bound connector such as a second Amazon account returns unsupported. The reason is honest: the reference has no enrollment primitive that lets a local collector drive a real browser session and ingest through the device-exporter path. The enroll route hardcodes source_kind: "local_device" and does no binding-aware validation, so there is no way to record that a collected binding is browser-collected rather than filesystem-read.

The add-owner-agent-control-surface design already named this exact gap and its three-part shape. This change turns that named gap into a reviewable construction packet so browser-bound enrollment becomes correct by construction for Amazon, Chase, ChatGPT, and future browser-bound connectors — without leaking browser automation into PDPP Core and without faking success before proof exists.

What Changes

• Add a browser_collector source kind to the reference connector-instance source-binding vocabulary, distinct from local_device. A browser_collector binding records that the binding is collected by a local collector driving a browser session, not by reading the device filesystem.
• Make device-exporter enrollment binding-aware: the enrollment-code and enroll routes SHALL derive the source kind from the connector manifest runtime_requirements.bindings (a browser binding → browser_collector; a filesystem binding → local_device) and SHALL reject a source-kind that contradicts the manifest.
• Require committed proof — a test plus a scrubbed fixture — that a local collector runs a browser-bound connector (Amazon) end-to-end through the device-exporter ingest path before any route flips Amazon from unsupported to a real next step.
• Define the owner-mediated initiation contract for browser-bound connectors: the intent route MAY return a typed enroll_browser_collector next step that carries an enrollment code but SHALL keep connection_active: false until the owner's collector enrolls, completes provider login locally, and ingests.
• Keep boundaries explicit: this is reference / Collection Profile implementation vocabulary, not PDPP Core. The bare browser binding name mismatch with the spec-defined browser_automation / browser_profile registry is acknowledged and deferred to its existing design note, not silently absorbed.

Capabilities

Modified Capabilities

• local-device-exporter-collection: add binding-aware enrollment gating, the browser_collector source kind, and a proof gate before browser-bound connectors advertise a real next step.
• reference-connector-instances: extend the durable source-binding identity to carry browser_collector as a peer of local_device so browser-collected and filesystem-collected bindings for the same connector type remain distinct.

Impact

• OpenSpec / design only in this lane. No primitive implementation here.
• Future implementation areas: reference-implementation/server/routes/ref-device-exporters.ts (enrollment-code + enroll), reference-implementation/server/routes/owner-connection-intent.ts (the browser_bound branch), the connector-instance source-binding types, and a committed Amazon browser-collector proof test + scrubbed fixture.
• Downstream: add-owner-agent-control-surface task 5.3 / 8.5 (Amazon second-account acceptance) unblocks only after the proof gate in this change is satisfied.