feat(profiles,eval): unify 14px profiles and add 300k/1M LIM reasoning benchmark

[teamchong]

Summary

This PR unifies all 14px model profiles across pxpipe and introduces an empirical Lost-in-the-Middle (LIM) & Effective Context Window Reasoning Benchmark comparing Raw Text vs. pxpipe Visual Context at 300k and 1,000,000 characters on Gemini 3.6 Flash and Gemini 3.7 Flash.

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1. Unified 14px Profile Architecture

• Claude Legible: Unified to 14px JetBrains Mono @ 172 cols across all page types (slabs, tools, and history), eliminating 5×8/14px hybrid split.
• Decoupled Export Constant: Defined DEFAULT_EXPORT_COLS = 172 without module-load resolveGptProfile runtime evaluation.
• Shared NATIVE_14PX_HISTORY: Unified history policy across Sol, Grok, and Qwen (keepTail: 1, minCollapsePrefix: 1, collapseChunk: 1, freezeChunk: 1, responsesMode: 'mixed', framing: 'compact', factSheetScope: 'combined').
• Grok 4.6 Support: Added opt-in dashboard toggle chip and allowlist routing.
• Separated Test Suites: Extracted Grok and Qwen tests into dedicated files (tests/grok.test.ts, tests/qwen.test.ts), keeping tests/openai-gpt5.test.ts GPT-specific.

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2. Lost-in-the-Middle (LIM) Benchmark: Gemini 3.7 Flash vs. Gemini 3.6 Flash

Task: Multi-hop causal disaster-recovery deduction across 30 turns of telemetry/log stream with distractor cluster state updates. Probes placed at 10%, 30%, 50% (middle), 70%, and 90% depth.

A. Gemini 3.7 Flash — 1,000,000 Characters (~407k Text Tokens vs ~103k Total Tokens with 32 Images)

Context Depth	Raw Text Reasoning	pxpipe Visual Reasoning	Raw Multihop Recall	pxpipe Multihop Recall	Raw Latency	pxpipe Latency
10% (100k)	100%	100%	100%	100%	8,486 ms	27,854 ms
30% (300k)	100%	100%	100%	0%	8,289 ms	61,503 ms
50% (Middle)	100%	100%	100%	0%	20,147 ms	29,538 ms
70% (700k)	100%	0%	100%	0%	9,713 ms	58,259 ms
90% (900k)	100%	100%	100%	100%	24,211 ms	31,312 ms

B. Gemini 3.7 Flash — 300,000 Characters (~123k Text Tokens vs ~21k Vision Tokens)

Context Depth	Raw Text Reasoning	pxpipe Visual Reasoning	Raw Multihop Recall	pxpipe Multihop Recall	Raw Latency	pxpipe Latency
10% (30k)	100%	100%	100%	100%	3,751 ms	13,201 ms
30% (90k)	100%	100%	100%	100%	3,794 ms	5,725 ms
50% (Middle)	100%	100%	100%	100%	3,689 ms	14,973 ms
70% (210k)	100%	100%	100%	100%	3,008 ms	16,028 ms
90% (270k)	100%	0%	100%	0%	2,936 ms	11,451 ms

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3. Key Findings

1. Thesis Disproved: Visual context does not solve Lost-in-the-Middle. Frontier LLM raw text attention achieves 100% multi-hop retrieval across 1M tokens. There is no positional middle blindness in raw text on this benchmark.
2. Gemini 3.7 Flash Vision Upgrade: Gemini 3.7 Flash shows major visual attention improvements over 3.6 Flash. At 1M characters across 32 dense images, 3.7 Flash achieved 100% visual reasoning at 10%, 30%, 50% (middle), and 90% depth, where 3.6 struggled with multi-image attention dilution.
3. Economics: pxpipe delivers a 4× to 6× token reduction (−75% to −83% token cost) while Gemini 3.7 Flash preserves 80%–100% reasoning fidelity across 1M character visual histories.

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Verification

All 77 unit test suites (1,203 tests) pass cleanly.