fix(desktop): use official logo in macOS installer

[t3-code]

summary

The macOS installer header used a Helvetica recreation of the brand. Replace it with the exact vector path and viewBox from apps/web/src/components/T3Wordmark.tsx in both stable and nightly backgrounds.

Only the top-left logo changes. Artwork, instructions, and installer layout are untouched. Follow-up to #10632.

verification

• Both SVGs parse successfully.
• Rendered stable and nightly at 640×432 and 1280×864 using resvg.
• Verified exact canonical logo path; pixel comparisons show no changes outside the top-left logo region at either size.
• git diff --check passes.
• Native macOS sips/Finder verification was not available on this Linux runner. These are renders of the actual background assets, not Finder screenshots; text uses the runner's fallback font.

before

after: nightly

after: stable

request provenance

requested by @juliusmarminge.

model: gpt-6-astra. harness: hermes agent.

[macroscopeapp]

Approvability

Verdict: Approved at 5a07ff8

Macroscope's review found this PR approvable — This is a small, self-contained presentation change limited to two ignored macOS DMG background SVGs, affecting installer branding only. It does not alter application logic, product defaults, deployment behavior, or sensitive functionality.

Notes:

• No code objects were reviewed. Approvability was decided on eligibility alone.

^{You can add or adjust custom eligibility rules. Learn more.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.6 KiB	13.6 KiB	+55 B (+0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.0 KiB	7.0 KiB	+4 B (+0.1%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.6 KiB	+51 B (+0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	57.0 KiB	57.1 KiB	+88 B (+0.2%)	66.4 KiB	✅
Codex	Live turn messages	8	10	+2 (+25.0%)	21	✅
Claude	Total thread wire	13.6 KiB	13.5 KiB	−23 B (−0.2%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	+1 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.5 KiB	6.5 KiB	−24 B (−0.4%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.8 KiB	57.8 KiB	−44 B (−0.1%)	66.4 KiB	✅
Claude	Live turn messages	9	8	−1 (−11.1%)	21	✅

Baseline: 12391bd · PR result: 5a07ff8 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 113.9 KiB
• Claude decoded thread snapshot: 114.6 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.