Validate PostscriptFragment offsets when parsing the footer

[robert3005]

Parser shouldn't crash, but error in these cases

[github-actions]

Polar Signals Profiling Results

Latest Run

Status	Commit	Job	Attempt	Link
🟢 Done	43c3b58		1	Explore Profiling Data

---

Powered by Polar Signals Cloud

[robert3005]

fix #8814

[github-actions]

Benchmarks: Vortex queries

Verdict: No clear signal (low confidence)
Attributed Vortex impact: +3.5%
Engines: DataFusion No clear signal (+8.3%, low confidence) · DuckDB No clear signal (-1.0%, low confidence)
Vortex (geomean): 0.995x ➖
Parquet (geomean): 0.978x ➖
Shifts: Parquet (control) -2.2% · Median polish +0.2%

How to read Verdict and Engines

• Verdict: Overall PR-level signal after subtracting baseline drift estimated from Parquet control rows. It can be Likely improvement, Likely regression, or No clear signal.
• Engines: Per-engine attribution. DataFusion is compared against DataFusion/Parquet controls; DuckDB is compared against DuckDB/Parquet controls. This answers whether each engine improved or regressed independently.
• Confidence: Based on directional consistency, share of rows above the noise floor, and control-run noise.

---

datafusion / vortex-file-compressed (1.028x ➖, 0↑ 0↓)

name	PR 43c3b58 (ns)	base 60c1227 (ns)	ratio (PR/base)
vortex_q00/datafusion:vortex-file-compressed	9868704	9622169	1.03
vortex_q01/datafusion:vortex-file-compressed	6315644	6124254	1.03

datafusion / parquet (0.950x ➖, 0↑ 0↓)

name	PR 43c3b58 (ns)	base 60c1227 (ns)	ratio (PR/base)
vortex_q00/datafusion:parquet	20254165	21179208	0.96
vortex_q01/datafusion:parquet	4577166	4850601	0.94

duckdb / vortex-file-compressed (0.997x ➖, 0↑ 0↓)

name	PR 43c3b58 (ns)	base 60c1227 (ns)	ratio (PR/base)
vortex_q00/duckdb:vortex-file-compressed	10182558	10093295	1.01
vortex_q01/duckdb:vortex-file-compressed	6120707	6216890	0.98

duckdb / parquet (1.007x ➖, 0↑ 0↓)

name	PR 43c3b58 (ns)	base 60c1227 (ns)	ratio (PR/base)
vortex_q00/duckdb:parquet	23516632	23382995	1.01
vortex_q01/duckdb:parquet	9464180	9386126	1.01

---

No file size changes detected.