test: expand pixi locator coverage

[karthiknadig]

Adds 7 new unit tests to pet-pixi (from 6 to 13 total).

New coverage:

• is_pixi_env(): conda-meta without pixi marker, no conda-meta directory
• get_pixi_prefix(): non-bin parent, bin parent but not pixi env, explicit prefix preference
• try_from(): name extraction from directory, rejection when explicit prefix is not pixi

Fixes #389

[github-actions]

Performance Report (Linux) ➖

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta	Change
Server Startup	1ms	1ms	0ms	1ms	N/A%
Full Refresh	65ms	488ms	53ms	12ms	20.0%

Results based on 10 iterations. P50 = median, P95 = 95th percentile.

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Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)

[github-actions]

Test Coverage Report (Linux)

Metric	Value
Current Coverage	75.7%
Base Branch Coverage	75.6%
Delta	.1% ✅

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Coverage increased! Great work!

[github-actions]

Performance Report (macOS)

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta
Server Startup	93ms	699ms	85ms	8ms
Full Refresh	185ms	39719ms	175ms	10ms

Results based on 10 iterations. P50 = median, P95 = 95th percentile.

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)

[github-actions]

Test Coverage Report (Windows)

Metric	Value
Current Coverage	72.62%
Base Branch Coverage	72.49%
Delta	0.13% ✅

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Coverage increased! Great work!

[github-actions]

Performance Report (Windows) ✅

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta	Change
Server Startup	10ms	14ms	11ms	-1ms	-9.1%
Full Refresh	168ms	2164ms	202ms	-34ms	-16.8%

Results based on 10 iterations. P50 = median, P95 = 95th percentile.

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)