feat: add missing CLI arguments for find command with env var fallbacks

[karthiknadig]

Adds CLI arguments to the find command that mirror the JSONRPC server's configure options, with PET_* environment variable fallbacks via clap's env attribute.

Changes

• Add --conda-executable / PET_CONDA_EXECUTABLE to find
• Add --pipenv-executable / PET_PIPENV_EXECUTABLE to find
• Add --poetry-executable / PET_POETRY_EXECUTABLE to find
• Add --environment-directories / PET_ENVIRONMENT_DIRECTORIES (comma-delimited) to find
• Add PET_CACHE_DIRECTORY env var fallback to existing --cache-directory on both find and resolve
• Wire new options through FindOptions → create_config() → Configuration
• Pass user-provided conda/poetry executables to find_and_report_missing_envs (previously hardcoded to None)
• Enable clap env feature in Cargo.toml

Fixes #353

[github-actions]

Test Coverage Report (Linux)

Metric	Value
Current Coverage	58.1%
Base Branch Coverage	58.3%
Delta	-.2% ❌

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Coverage decreased. Please add tests for new code.

[github-actions]

Performance Report (Linux) ✅

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta	Change
Server Startup	1ms	1ms	1ms	0ms	0%
Full Refresh	77ms	502ms	78ms	-1ms	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 (Windows)

Metric	Value
Current Coverage	54.44%
Base Branch Coverage	54.58%
Delta	-0.14% ❌

---

Coverage decreased. Please add tests for new code.

[github-actions]

Performance Report (Windows) ➖

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta	Change
Server Startup	12ms	15ms	10ms	2ms	20%
Full Refresh	201ms	413ms	181ms	20ms	11%

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]

Performance Report (macOS)

Metric	PR (P50)	PR (P95)	Baseline (P50)	Delta
Server Startup	58ms	507ms	48ms	10ms
Full Refresh	104ms	29452ms	93ms	11ms

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)