fix(archdocs): guard against start_line > end_line in source snippet extraction

[greynewell]

Summary

• In pssg/build/build.go, when extracting source code snippets from entity pages, the code does lines[sl-1:el] after checking sl <= len(lines) && el <= len(lines)
• If sl > el (start_line > end_line in the API response), this creates a reversed slice range and panics with slice bounds out of range
• Add sl <= el to the bounds guard so malformed line numbers skip the extraction instead of crashing the supermodel docs build

Test plan

• go build ./... passes
• Manual: supermodel docs on a repo with normal source data still shows source snippets correctly

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Fixed source-code extraction validation to prevent invalid line ranges where the start line exceeds the end line, improving reliability.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: e5dceda2-3cc5-4abe-b2c3-b435708cae20

📥 Commits

Reviewing files that changed from the base of the PR and between b8d16ff and 58e05ce.

📒 Files selected for processing (1)

• internal/archdocs/pssg/build/build.go

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Walkthrough

A boundary validation fix in the source-code extraction logic: the slice range check now verifies that the start line doesn't exceed the end line (sl <= el), preventing invalid extraction ranges where the indices are reversed.

Changes

Cohort / File(s)	Summary
Boundary Validation internal/archdocs/pssg/build/build.go	Added validation condition sl <= el to the renderEntityPage function's slice bounds check, ensuring start line never exceeds end line in source-code extraction.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

A line of defense, now standing tall,
Where start must not exceed the call,
No more reversed ranges in the night,
One tiny check sets bounds just right! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly and specifically describes the main change: adding a guard to prevent start_line > end_line in source snippet extraction, which matches the actual code change.
Description check	✅ Passed	The description covers the what, why, and test plan sections from the template, explaining the bug, the root cause, the fix, and the testing approach clearly.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix-pssg-slice-bounds

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