fix(types): close 3 svelte-check errors — sessions prop + invoke mock (#214 PR4) (#227)

Part of the #214 cleanup. Brings `npm run check` from 50 -> 47 errors
(closes 3). Scoped to the two genuinely mechanical fixes from #214's
proposed PR4 — groups E and M turned out to need real investigation,
see below.

## Changes

- **Group H** — `routes/sessions/+page.svelte` passed
  `sessionSummary={sessionStore.selectedSessionSummary}` to
  `SessionDetailPanel`. Neither side exists anymore: `SessionStoreState`
  has no `selectedSessionSummary`, and `SessionDetailPanel`'s `Props` is
  `{ detail, onClose }`. The prop was already dead — removed the line.
- **Group K** — `tests/helpers/invokeMock.ts` typed the `invoke`
  mock implementation's `args` as `Record<string, unknown>`. Tauri's
  `invoke` signature is `(cmd, args?: InvokeArgs, ...)` and `InvokeArgs`
  is wider (e.g. `number[]`), so the narrower callback param made the
  mock unassignable. Widened to `InvokeArgs` and cast at the boundary
  where it's handed to the ergonomic `handler` callback.

## Deferred from #214's PR4 grouping

- **Group E** (keybindings `"Input"` context, 6 errors) — not a fixture
  cleanup. The tests pass at runtime (31/31) but reference `'Input'`,
  which is in neither `KEYBINDING_CONTEXTS` nor `KEYBINDING_ACTIONS`;
  they only pass via cross-test override state. Adding `'Input'` to the
  `KeybindingContext` union would be a phantom-value behavior change;
  rewriting the tests needs care around their state dependencies.
- **Group M** (`AgentMemoryPanel` `selectedProject`, 1 error) — a latent
  runtime bug, not drift. `projectsStore` has no project-selection
  concept at all, so `projectsStore.selectedProject?.path ?? null` is
  always `null` — the panel's project-scope memory silently never gets
  a path. Needs a data-flow decision (prop vs. route param).

## Test plan

- [x] `npm run check` — 50 errors (down from 53 on `main`)
- [x] `npx vitest run` (sessionStore + helpers consumers) — pass
- [x] Zero new errors

Co-authored-by: Tyler Gray <tylerg@emergentsoftware.net>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 3 people

src/routes/sessions/+page.svelte

@@ -139,7 +139,6 @@
 		{:else if sessionStore.sessionDetail}
 			<SessionDetailPanel
 				detail={sessionStore.sessionDetail}
-				sessionSummary={sessionStore.selectedSessionSummary}
 				onClose={() => sessionStore.clearSession()}
 			/>
 		{/if}

src/tests/helpers/invokeMock.ts

@@ -1,5 +1,6 @@
 import { vi } from 'vitest';
 import { invoke } from '@tauri-apps/api/core';
+import type { InvokeArgs } from '@tauri-apps/api/core';
 
 /**
  * Set up command-routing mock for Tauri invoke.
@@ -33,7 +34,7 @@ export function mockInvokeResponses(responses: Record<string, unknown>): void {
 export function mockInvokeHandler(
 	handler: (cmd: string, args?: Record<string, unknown>) => unknown
 ): void {
-	vi.mocked(invoke).mockImplementation(async (cmd: string, args?: Record<string, unknown>) => {
-		return handler(cmd, args);
+	vi.mocked(invoke).mockImplementation(async (cmd: string, args?: InvokeArgs) => {
+		return handler(cmd, args as Record<string, unknown> | undefined);
 	});
 }