feat(named-agents): sidebar view, synthetic provider, auto-save, snapshot semantics

Implement the frontend of the Named Agents feature (plan §5-§9):
- New features/named-agents module: pure logic (types re-exported from
  @dispatch/wire + transport-contract, validation, provider/model options,
  snapshot helpers, network normalizers, auto-save status model) + an injected
  auto-save controller (name debounce, immediate provider/model save, monotonic
  stale-response guard) + the collapsible sidebar card view.
- Store: /named-agents CRUD + boot seed; selectModel(model, snapshot?) persists
  the raw model WITH the namedAgent snapshot; draft promotion carries it;
  refreshModel restores ModelResponse.namedAgent.
- Chat store setNamedAgent (sends namedAgent on chat.send); Tab.snapshot +
  setSnapshot (retained across rename/remove, persisted with tabs).
- Model selector: synthetic Named Agents provider ALWAYS first; selecting one
  resolves to the raw model + records a snapshot; a retained snapshot of a
  renamed/removed agent still displays as unavailable (plan §7).
- Composition root wires the view (viewKinds + loaded-modules manifest) + feeds
  the selector.

Tests: logic + controller + selector + app-store CRUD (1246 pass), typecheck 0,
biome clean (only pre-existing config infos pending a future migrate), build OK.

1 files changed, 76 insertions, 0 deletions

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+# Backend handoff — Dispatch Web (tracked; kept current at every milestone)
+
+> This living document is the cross-repo courier between the FE (this repo) and the BACKEND
+> (`../backend`, a separate repo). `lsp` does not span the seam — the USER carries updates across.
+> Per AGENTS.md "Backend seam": FE contract changes are edited + consumers updated here; BACKEND
+> contract changes are REPORTED UP here, and on the new version the FE re-pins the `file:` dep,
+> re-mirrors `.dispatch/*.reference.md`, and updates consumers. NEVER edit the backend repo.
+
+## Milestone: Named Agents — FE scope (feature/named-agents)
+
+**Slice status:** COMPLETE + committed. The FE Named Agents feature is implemented end-to-end against
+the backend contract that shipped in parallel (both repos on the `named-agents` worktree).
+
+### What the FE built
+- **New feature module** `src/features/named-agents/`:
+  - `logic/types.ts` — re-exports `NamedAgent` + `NamedAgentSelectionSnapshot` from `@dispatch/wire`
+    and the `/named-agents` HTTP request/response types (`NamedAgentsResponse`, `NamedAgentResponse`,
+    `DeleteNamedAgentResponse`, `CreateNamedAgentRequest`/`NamedAgentInput`) from
+    `@dispatch/transport-contract`; defines the local port/result types.
+  - `logic/validate.ts` — pure name/model validation (nonempty, case-insensitive-unique, canonical
+    `<provider>/<model>`).
+  - `logic/options.ts` — provider/model dropdown derivation from the `GET /models` catalog (numbered
+    OpenCode numeric sort + friendly labels, matching the model picker).
+  - `logic/snapshot.ts` — pure snapshot helpers (`snapshotFor`, `findNamedAgent`).
+  - `logic/normalize.ts` — network-seam normalizers for the untyped `/named-agents` JSON.
+  - `logic/auto-save.ts` — pure auto-save status/validity model (`idle/dirty/saving/saved/error`),
+    `draftValidity`, `isDirty`, `saveStatusLabel`.
+  - `ui/controller.svelte.ts` — the injected auto-save SHELL (debounce for name edits, immediate save
+    for provider/model, monotonic sequence guard so an older response never overwrites a newer edit;
+    create/update/remove ports injected).
+  - `ui/NamedAgentCard.svelte` + `ui/NamedAgentsView.svelte` — the collapsible sidebar view (cards
+    with name/provider/model controls + status line + Remove + Add + empty state).
+  - `index.ts` + `manifest`.
+- **Store** (`src/app/store.svelte.ts`): `namedAgents` state + CRUD (`refreshNamedAgents` /
+  `createNamedAgent` / `updateNamedAgent` / `deleteNamedAgent`) over `GET/POST/PUT/DELETE /named-agents`;
+  `namedAgentSnapshot` reactive state; `selectModel(model, snapshot?)` persists the raw model via
+  `PUT /conversations/:id/model` WITH the `namedAgent` snapshot; draft promotion carries the snapshot;
+  `refreshModel` restores the persisted `ModelResponse.namedAgent`.
+- **Chat store** (`features/chat/store.svelte.ts`): `setNamedAgent(snapshot)` so `chat.send` includes
+  `namedAgent` at conversation creation (draft path).
+- **Tabs** (`features/tabs`): optional `Tab.snapshot` + `setSnapshot` reducer/store method (snapshot
+  retention survives rename/remove + persists to localStorage with tabs).
+- **Model selector** (`chat/model-select.ts` + `ModelSelector.svelte`): the synthetic **Named Agents**
+  provider is ALWAYS first in the provider list; selecting a Named Agent resolves it to the raw model +
+  records the snapshot; the UI shows `Named Agents -> <name>`. A retained snapshot of a renamed/removed
+  agent still displays as an `(unavailable)` option (plan §7).
+- **Composition root** (`src/app/App.svelte`): "Named Agents" view kind (+ loaded-modules manifest),
+  `NamedAgentsView` wired to store CRUD ports, ModelSelector fed `namedAgents`/`namedAgentSnapshot` +
+  `handleSelectNamedAgent`.
+- **Tests:** pure logic (validate/options/snapshot/normalize) + auto-save status + controller
+  (debounce, sequence guard, create/update/remove) + ModelSelector named-agent provider + app-store
+  CRUD/snapshot. 1246 tests pass (up from 1226 before the slice), typecheck 0, biome clean (only the 2
+  pre-existing config infos), `vite build` succeeds.
+
+### Pinned contract versions + mirrors
+- `@dispatch/wire`: consumed (now exports `NamedAgent` + `NamedAgentSelectionSnapshot`). Mirror
+  `.dispatch/wire.reference.md` updated with a 2026-08-20 delta note.
+- `@dispatch/transport-contract`: consumed (now exports the `/named-agents` types +
+  `ChatRequest.namedAgent`/`ModelResponse.namedAgent`/`SetModelRequest.namedAgent`). Mirror
+  `.dispatch/transport-contract.reference.md` updated with a 2026-08-20 delta note.
+- `@dispatch/ui-contract`: unchanged (no surface-based named-agent mechanism — it is a regular FE view).
+
+### Open asks / for the backend
+- None blocking. The FE aligns with the backend's shipped contract. Confirm the backend's
+  `list_agent_models` returns ONLY named agents (not the raw catalog) and that `summon_agent` accepts
+  `agent` (name/id) resolving locally to the raw model with an `unknown-agent` error — the FE relies on
+  the `/named-agents` surface for CRUD + the model selector; the agent-tool behavior is purely backend.
+
+### Findings
+- The backend contract shipped the snapshot on `ChatRequest`/`ModelResponse`/`SetModelRequest` (richer
+  than the plan's "recommended HTTP surface"); the FE uses it for the model-selector + draft promotion
+  paths so backward/raw-model conversations are unaffected.
+
+### Likely next asks
+- A live probe (after the backend boots) exercising `/named-agents` CRUD + the synthetic-provider
+  selection round-trips, when the user has the backend up.
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