fix(site): show negative history deltas

[Seungpyo1007]

Summary

• show negative dataset history deltas instead of treating decreases as a baseline
• show category-level increases and decreases in the history timeline
• put History before Playground in the nav and hero CTA flow
• stop PR metadata automation from adding persistent tracker issue references that can auto-close long-running issues

Tracking

• Closes Track homepage and site improvements #19

Verification

• npm.cmd run build
• git diff --check

[TechEngineBot]

TechEngine change review: PASS

• PR: fix(site): show negative history deltas #21
• Ref: feat/site
• Commit: cd07f7b
• Requested by: @Seungpyo1007
• Run: https://github.com/GetTechAPI/TechEngine/actions/runs/27740990927

Check	Result
python -m app.validate	PASS
python integrity_check.py TechAPI/data --strict	PASS
cd TechAPI/site && npm ci && npm run build	PASS

Changed data

Category	Added	Modified	Deleted	Added verified	Added unverified	Added Kaggle-sourced
brand	0	0	0	0	0	0
soc	0	0	0	0	0	0
smartphone	0	0	0	0	0	0
gpu	0	0	0	0	0	0
cpu	0	0	0	0	0	0

Changed record examples

• No data file changes detected.

Heuristic review

• Heuristic warnings: none found.

Changed site

Area	Added	Modified	Deleted
homepage/site	0	3	0

Modified site files

• site/src/pages/index.astro
• site/src/scripts/techapi.js
• site/src/styles/techapi.css

[TechEngineBot]

TechEngine validation stats: PASS

• PR: fix(site): show negative history deltas #21
• Ref: feat/site
• Commit: cd07f7b
• Run: https://github.com/GetTechAPI/TechEngine/actions/runs/27740990927

Data summary

Category	Total	Verified	Unverified	Missing verified	Verified %
brand	129	0	0	129	n/a
soc	123	58	65	0	47.2%
smartphone	367	184	183	0	50.1%
gpu	2030	0	2030	0	0.0%
cpu	3977	976	3001	0	24.5%
all	6626	1218	5279	129	18.7%

Validation notes

• Full advisory outlier listings are suppressed on successful runs because they are dataset-wide and mostly stable between PRs.
• Failure runs still include a detailed log excerpt for debugging.

Key output:

## app.validate
## integrity_check.py --strict
loaded CPU=3977 GPU=2030
✅ integrity gate: no hard anomalies.

Integrity section	Flagged lines
structural	0
CPU name/tier consistency (desktop mainstream only)	0
CPU single>multi (cinebench/geekbench — should be multi>=single)	0
CPU era-vs-score outliers	8
CPU cross-source ratio outliers (possible wrong-variant)	152
GPU cross-source ratio outliers + sanity	18

Homepage build:

06:25:46 [build] 2 page(s) built in 2.44s
06:25:46 [build] Complete!