fix(tray): log tray icon failures instead of panicking

[rsanheim]

Before Submitting This PR

Please confirm you have done the following:

• I have searched existing issues and pull requests (including closed ones) to ensure this isn't a duplicate
• I have read CONTRIBUTING.md

If this is a feature or change that was previously closed/rejected:

• I have explained in the description below why this should be reconsidered
• I have gathered community feedback (link to discussion below)

Human Written Description

I was doing perf testing against Handy with agents, and agents like to create worktrees. Sometimes agents like to build a full mac app locally inside a worktree and run it for their own testing loops...and then leave that sad dev build of Handy running w/ a tray icon pointing to a worktree path.

Then the worktree was cleaned up, and Handy exploded gloriously 😀 .

So, this adds error handling around the tray icon code to ensure that errors there don't panic and blow up the main thread....I know the worktree use-case is probably a dev-only edge case. But I can think of of other ways that the icon resource path could get broken (file corruption, permissions, misbehaving updates). And being able to use worktrees for dev/test is nice too.

Oh, added some tests.

Related Issues/Discussions

Fixes #
Discussion: No exact matching issue or PR found in targeted searches for:

• "tray icon" panic
• "failed to resolve" tray
• tray_recording
• set_icon tray

Related but not duplicate:

• Handle microphone init failure without aborting #945 handles microphone init panic paths.
• feat(tray): add transcribing state and update icons #44 added tray icon states.

Community Feedback

n/a

Testing

Automated local checks run:

• cargo fmt -- --check passed.
• cargo test tray::tests::tray_icon_resolution_failure_is_reported_instead_of_panicking passed.
• cargo test passed: 66 tests passed, 0 failed.
• bun run lint passed.
• bun run check:translations passed.
• bun run build passed with the existing Vite large chunk warning.
• ./node_modules/.bin/prettier --check PR_DRAFT.md CONTRIBUTING_TASKS.md passed.

Checks with caveats:

• cargo clippy --all-targets --all-features -- -D warnings ran, but failed on existing unrelated warnings outside src-tauri/src/tray.rs.
• bun run format:check ran, but failed before Rust formatting because Prettier found existing formatting issues in AGENTS.md and untracked tools/macos-audio-perf/.build/ artifacts.

Screenshots/Videos (if applicable)

n/a

AI Assistance

• No AI was used in this PR
• AI was used (please describe below)

If AI was used:

• Tools used: Codex and Claude Code
• How extensively: Plenty -- Lots - helped isolate the issue after the fact, and draft the fix. Then helped me refactor to something w/ less LOC. Helped w/ the tests. I pointed it at the worktree prune as a cause, tho, so I got that going for me.

[cjpais]

Thanks