feat(fresh-agent): render opencode-pty notifications as agent text (display-only)

[danshapiro]

What

opencode-pty plugin notification messages (the machine-injected <pty_exited> / <pty_waited> / <pty_wait_timeout> blocks that arrive as genuine user-role turns) now render everywhere in the fresh-agent UI as agent text: agent label and bubble styling, markdown rendering, folded into adjacent agent turns as continuations, no minimap tick or hover preview, and agent-parity toolbar affordances. The minimap rail now shows only real human prompts.

Display-only by construction: a single shared pure classifier (reclassifyPtyNotificationTurns in shared/fresh-agent-turns.ts) is composed first inside the existing displayTurns memo in FreshAgentTranscript.tsx — the same choke point that already rewrites synthetic tool-result user turns for display. The wire snapshot contract ("exactly what the model sees"), store turns, the rollback stepper's raw user-role step counts (sum-to-rollback.undoneDepth pin), and freshAgentSnapshotHasUserTurn are all untouched; a guard test pins the stepper raw rule.

Changes

• shared/fresh-agent-turns.ts — additive classifier (leading-tag detection, first-text-item-then-summary extraction, identity-preserving for non-matches, never mutates input)
• src/components/fresh-agent/FreshAgentTranscript.tsx — one import + the memo composition (2 lines)
• test/unit/shared/fresh-agent-turns.test.ts — 6 classifier unit tests
• test/unit/client/components/fresh-agent/FreshAgentTranscript.test.tsx — 5 display pins (label/bubble, markdown path, continuation fold, toolbar parity, rollback raw-rule guard)
• test/e2e-browser/specs/fresh-agent-pty-notification-display.spec.ts — new cloud-legal e2e: freshopencode pane seeded with a realistic <pty_exited> conversation; asserts agent article, no You, exactly one minimap tick

Verification

• TDD red→green at every level (unit RED 4-fail/guard-pass; e2e RED→GREEN with explicit attribution criteria)
• Impacted set: 431/431 unit tests; typecheck:client clean; lint clean on touched files
• e2e green on the cloud backend at the committed HEAD (1 passed, 7.1s, server self-identifies the commit)
• Full-suite gate at HEAD: client + source-runtime green; electron + electron-runtime lanes green at HEAD; rust red with exactly the 11 pre-existing base failures (session-handoff/ownership area — user-authorized exception recorded in the plan's Global Constraints; this PR touches no Rust code, and the failure list matches the base receipts name-for-name)
• Reviews: task reviews PASS/APPROVED (both), whole-branch review PASS/APPROVED, independent delta review PASSED with zero findings (different model family, validated tag detection against the opencode-pty plugin's upstream source)

Includes the implementation plan (docs/plans/2026-09-18-pty-notification-display-role.md) with the recorded user-authorized red-base exception.