feat(browser): retain compact scenario summaries and selected views (#7120)

Retain complete browser scenario Evidence while delivering compact summaries and selected step, event, transaction and text views through shared CLI/MCP workflows. Preserve initial CLI failures across cleanup retries and validate with real Chromium/TodoMVC.

Co-authored-by: Kaoru0822 <208281322+kaoru0822-kitauji@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/browser-scenario-contract.md

@@ -621,3 +621,58 @@ rules and preserve the same missing fact.
 Network normalization also commits the removal of capture-local transaction IDs,
 attribution to the requesting step, and unordered transaction comparison. These
 built-in rule identities participate in the normalization digest.
+
+## Summary delivery and retained views
+
+`capture_browser_scenario` accepts `detail: "summary"` to retain the complete
+capture in the MCP session and return its summary. The default remains
+`complete`. Delivery detail does not change scenario parameters or identity.
+
+The summary reports each step's status, error, URL and captured/missing/truncated
+section names. It omits `not_requested` sections and repeated `before_url` values.
+The accessibility tree comes from the first unsuccessful step, or the final
+step on success; when that step captured no tree, its nearest earlier captured
+tree is identified explicitly. Event and network counts cover retained records,
+with capture omissions reported separately.
+
+For the one-shot CLI, save the complete Evidence before selecting a summary:
+
+```bash
+rea capture-browser-scenario scenario.json --detail summary --evidence_output /absolute/path/scenario-evidence.json --json
+```
+
+Use the returned `normalized_result.parent_evidence_id` with
+`inspect_analysis_view` source `{kind: "retained-evidence", evidence_id: "..."}`.
+For a CLI bundle, use an `evidence-file` source with its absolute path and the
+parent Evidence ID. Views read the recorded capture; they never replay actions.
+
+- `{kind: "summary"}` returns the same overview.
+- `{kind: "browser-scenario", collection: "steps", step_indices: [2], artifacts: ["accessibility"], offset: 0, limit: 1}` returns selected recorded steps and artifacts.
+- `{kind: "browser-scenario", collection: "events", event_kinds: ["response"], transaction_ids: ["request-2"], offset: 0, limit: 20}` pages selected events with original item indices.
+
+Omitted filters select all; empty arrays select none. Pagination counts matching
+retained rows. Exhausting a page does not establish capture completeness or
+current application state.
+
+Transaction pages use `{kind: "browser-scenario", collection: "transactions", limit: 20}`.
+Their stable identity is the parent Evidence ID plus `transaction_id`; each row
+keeps original event indices. Metadata events are returned by default. Select
+`event_kinds: ["network-content"]` for recorded bodies and header values, or
+`event_kinds: []` for identity and indices alone. A `step_indices` filter selects
+a whole transaction when any retained event belongs to a selected step; this
+is receipt attribution, not proof that the action caused the request.
+
+For a large retained tree, request `{kind: "browser-scenario", collection: "text",
+step_index: 10, artifact: "accessibility", offset: 0, limit: 2048}`. `dom` is also
+supported. Offsets and limits count UTF-16 code units. The full artifact digest
+and byte size remain attached to each page. Missing, truncated and unrequested
+text stay explicit; source truncation counts are preserved without treating an
+exhausted page as a complete capture.
+
+Network summary counts include every retained transaction identity, including
+those whose request event was dropped. Missing request events, conflicting
+metadata and observed request failures have separate counts. `transactions` is
+`null` when network observation was unrequested or its legacy selection is
+unknown and there are no retained transactions; an observed empty inventory is
+`0`. Full capture omissions remain available and each page carries source
+completeness, dropped-event counts and omitted-transaction accounting.