fix(host-daemon): avoid stack overflow listing large directory trees

[yazydzhi]

Fixes #2362.

Problem

`listPathsRecursively` in `apps/host-daemon/src/command-handlers/file-list.ts` merges each subdirectory's results with:

```ts
results.push(...(await listPathsRecursively({ ...args, dir: fullPath })));
```

`Array.prototype.push(...arr)` spreads every element as a call argument. Once an accumulated subtree crosses V8's argument-count ceiling (~100k, engine-dependent), this throws `RangeError: Maximum call stack size exceeded` instead of returning. Any caller of file listing/search (a plugin's `listTree`, project file search, etc.) on a large enough workspace — a big Obsidian vault, a large monorepo — sees this surface as an opaque `HTTP 502`.

Fix

Replace the spread-push with a plain loop, which has no argument-count limit:

```ts
const childResults = await listPathsRecursively({ ...args, dir: fullPath });
for (const childResult of childResults) results.push(childResult);
```

Testing

Added a regression test that creates a 150k-file subtree and asserts `listPathsRecursively` returns instead of throwing.

• Confirmed the new test reproduces the exact `RangeError: Maximum call stack size exceeded` against the pre-fix code (stashed the fix, ran the test, same error/stack as reported).
• With the fix applied, all 15 tests in `file-list.test.ts` pass (`vitest run --config vitest.config.ts` in `apps/host-daemon`).

Test plan

• `vitest run` in `apps/host-daemon` — 15/15 passing
• Verified the new test fails with the exact reported error on the pre-fix code