chore: remove old handoff docs, plans, review reports, and task lists from rootHEADmaindev

Removed 40+ markdown files that were cluttering the repo root:
- frontend-*-handoff.md (28 files) — historical API contract handoffs, features all implemented
- backend-to-fe-handoff.md, backend-to-fe-handoff-2.md — old handoff docs
- broken-chat-repair-handoff.md — old repair handoff
- PLAN-mcp.md, PLAN-per-edit-diagnostics.md — old planning docs
- ai-review-report.md, crash-review-report.md — one-time review reports
- tasks.md, HANDOFF.md — outdated status docs (git log is the source of truth)

Kept: AGENTS.md, GLOSSARY.md, ORCHESTRATOR.md, README.md
Also: gitignored ai-review-report.md so future Gemini reviews don't commit it

1 files changed, 0 insertions, 91 deletions

diff --git a/frontend-model-persistence-handoff.md b/frontend-model-persistence-handoff.md
deleted file mode 100644
index 912cea6..0000000
--- a/frontend-model-persistence-handoff.md
+++ /dev/null
@@ -1,91 +0,0 @@
-# Frontend handoff — per-conversation model persistence
-
-## What changed
-
-A chat's selected provider + model is now **persisted per conversation**
-(like `cwd` and `reasoningEffort` already are). Opening a conversation in a new
-browser session recalls the originally selected model instead of defaulting to
-the server default.
-
-## Contract version bump
-
-`@dispatch/transport-contract` `0.19.0 → 0.20.0` — re-pin the `file:` dep and
-re-mirror `.dispatch/transport-contract.reference.md`.
-
-## New types (additive)
-
-```ts
-// GET /conversations/:id/model
-export interface ModelResponse {
-  readonly conversationId: string;
-  readonly model: string | null;  // <credentialName>/<model> form, or null
-}
-
-// PUT /conversations/:id/model
-export interface SetModelRequest {
-  readonly model: string | null;  // null clears the persisted selection
-}
-```
-
-## New endpoints
-
-### `GET /conversations/:id/model`
-Returns `ModelResponse`. `model` is `null` when never set (the server then
-resolves turns using the default provider + model).
-
-### `PUT /conversations/:id/model`
-Body: `SetModelRequest`. Set `model` to a `<credentialName>/<model>` string
-(one of the values from `GET /models`) to persist it. Set `model` to `null`
-to clear the persisted selection. Returns `ModelResponse` with the resulting
-value.
-
-## What the FE should do
-
-1. **On conversation open** — call `GET /conversations/:id/model` to fetch the
-   persisted model. If non-null, set the model selector to that value. If null,
-   use the global default (current behavior).
-
-2. **On model select** — call `PUT /conversations/:id/model` with the selected
-   model name (`<credentialName>/<model>` form). This persists it so future
-   turns (and new browser sessions) use the same model.
-
-3. **On model clear** (if the FE supports clearing back to default) — call
-   `PUT /conversations/:id/model` with `{ model: null }`.
-
-4. **No `ChatRequest.model` change needed** — the FE may continue sending
-   `model` on `chat.send` (per-turn override); the backend persists it. Or the
-   FE may omit `model` on `chat.send` and rely on the persisted value — the
-   backend resolves it. Either way works.
-
-## Backend behavior
-
-- **Per-turn override** (`ChatRequest.model` / `chat.send` model) takes
-  precedence and is persisted.
-- **No per-turn override** → backend checks `getModel(conversationId)` → if
-  non-null, uses it; if null, falls through to the default provider.
-- **Warm path** also resolves the model from persistence when no explicit
-  override is given (parity with real turns).
-
-## No FE handoff needed for tasks 1 & 2
-
-- **Task 1** (workspace tab broadcast): already couriered to 29ae by a prior
-  orchestrator agent (`frontend-workspace-open-handoff.md`).
-- **Task 2** (system-prompt cwd reconstruction): backend-only fix, no contract
-  version bump, no FE action needed.
-
-## Assumptions made (user was away)
-
-1. **Persist the model name string** (`<credentialName>/<model>` form), not
-   the provider/credential separately — the model name already encodes both
-   (the credential binds to a provider). This mirrors how the CLI sends
-   `--model` and how `ChatRequest.model` works.
-2. **No model validation on PUT** — the backend doesn't validate the model
-   name on `PUT /conversations/:id/model` (it's just a string). The provider
-   resolves it at turn time; an unknown model → turn error, not a 400. This
-   matches the contract doc on `SetModelRequest`.
-3. **Empty string clears** — `setModel(id, "")` deletes the key. The HTTP
-   `PUT` with `{ model: null }` maps to this. This is an implementation detail
-   the FE doesn't need to know about (it sends `null`).
-4. **No `model` field on `ConversationMeta`** — following the precedent of `cwd`
-   and `reasoningEffort` (which are NOT on `ConversationMeta` but fetched via
-   dedicated endpoints). The FE calls `GET /conversations/:id/model` to read.