Fix terminal special character rendering

[shusingh]

Summary

• decode PTY output as UTF-8 strings before sending terminal data to the renderer
• use the app's code font stack for xterm instead of the browser default monospace font
• cover the PTY encoding option in the shell service test

Fixes #1789.

Tests

• pnpm exec biome check apps/code/src/main/services/shell/service.ts apps/code/src/main/services/shell/service.test.ts apps/code/src/renderer/features/terminal/services/TerminalManager.ts
• pnpm --filter code test src/main/services/shell/service.test.ts
• pnpm --filter code exec tsc -p tsconfig.node.json --noEmit --pretty false
• pnpm --filter code exec tsc -p tsconfig.web.json --noEmit --pretty false

[greptile-apps]

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
apps/code/src/main/services/shell/service.test.ts:297-307
**Redundant test — encoding already asserted elsewhere**

The existing "creates a new shell session" test (line 189) was also updated in this PR to include `encoding: "utf8"` in its `objectContaining` assertion, making this standalone test a duplicate. Both tests call `service.create("session-1")` and assert the same `encoding` property on the same spawn call, violating OnceAndOnlyOnce. The new test can be removed; the encoding expectation is already covered.

_{Reviews (1): Last reviewed commit: "Fix terminal special character rendering" | Re-trigger Greptile}

[greptile-apps]

Redundant test — encoding already asserted elsewhere

The existing "creates a new shell session" test (line 189) was also updated in this PR to include encoding: "utf8" in its objectContaining assertion, making this standalone test a duplicate. Both tests call service.create("session-1") and assert the same encoding property on the same spawn call, violating OnceAndOnlyOnce. The new test can be removed; the encoding expectation is already covered.

Prompt To Fix With AI

This is a comment left during a code review.
Path: apps/code/src/main/services/shell/service.test.ts
Line: 297-307

Comment:
**Redundant test — encoding already asserted elsewhere**

The existing "creates a new shell session" test (line 189) was also updated in this PR to include `encoding: "utf8"` in its `objectContaining` assertion, making this standalone test a duplicate. Both tests call `service.create("session-1")` and assert the same `encoding` property on the same spawn call, violating OnceAndOnlyOnce. The new test can be removed; the encoding expectation is already covered.

How can I resolve this? If you propose a fix, please make it concise.

[shusingh]

Good catch, thanks. I removed the redundant test and kept the encoding assertion in the existing session creation test. Checks are passing.

[greptile-apps]

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
apps/code/src/main/services/shell/service.test.ts:188-203
**`createCommandSession` encoding untested; parameterised test preferred**

The PR adds `encoding: PTY_ENCODING` to both `create` (interactive shell) and `createCommandSession` (line 219 of `service.ts`), but the test assertion only covers the `create` path — `createCommandSession` has no test coverage at all. Per the team's "Expresses every idea" rule and preference for parameterised tests, a single `it.each` over both spawn call sites would verify the encoding fix uniformly without duplicating setup.

_{Reviews (2): Last reviewed commit: "Fix terminal special character rendering" | Re-trigger Greptile}

[shusingh]

Updated the test coverage to use a parameterized test for both create and createCommandSession, so the PTY UTF-8 encoding option is asserted on both spawn paths without duplicating the create-session test. Focused shell service test and Biome check are passing locally.

[shusingh]

Updated to cover both PTY spawn paths with a single parameterized test, including createCommandSession. The focused shell service test and Biome check pass locally.

[greptile-apps]

_{Reviews (3): Last reviewed commit: "Fix terminal special character rendering" | Re-trigger Greptile}

[charlesvien]

LFG