GCP integration + v0.3 frontend + intro animation

[Vector897]

Summary

• Vertex AI Gemini 2.0 Flash wired as judge/scorer via llm.py auto-routing (falls back to OpenRouter when GCP_PROJECT not set)
• BigQuery corpus layer (backend/app/data/bigquery.py) — whetstone.corpus table auto-provisioned on startup; /api/corpus/search prefers BQ over SQLite when GCP is configured
• Cloud Run deployment — Dockerfile + .dockerignore + .gcloudignore (excludes pdf_env/ symlink that causes WinError 1920 on Windows)
• Frontend v0.3 — 6/6 hackathon bonuses: persona picker (Hardball/Slippery/Stone Wall), adaptive difficulty badge, voice mode (Web Speech API en-GB), streak counter + sparklines, turning-point replay modal, BonusBar chip row
• Intro animation — frontend/intro.mp4 served via /intro.mp4 FastAPI route; fullscreen overlay plays before app loads, Skip › button, graceful fallback on video error
• README.md — English project description with hero image (frontend/demo.png), three-arenas table, tech stack, run/deploy commands, hackathon compliance table
• SQLite migration — ALTER TABLE adds persona + difficulty columns to existing DBs without destroying data

GCP track checklist

Service	Usage
Cloud Run	Main app deployment (europe-west2)
Vertex AI	Gemini 2.0 Flash as judge/scorer/referee LLM
BigQuery	whetstone.corpus — SEC EDGAR + CUAD clause corpus

Test plan

• uvicorn app.main:app --app-dir backend starts without errors
• GET /api/health returns gcp.vertex_ai: true when GCP_PROJECT is set
• Opening http://localhost:8000 shows intro video → Skip → loading bar → Dojo tab
• Persona picker appears before each session; selection persists in session state
• Dashboard tab renders without React hook errors
• GET /api/corpus/search?clause_type=liability_cap returns source: bigquery when BQ is configured

Deploy command

cd D:\Whetstone
gcloud run deploy whetstone \
  --source . --port 8080 --allow-unauthenticated \
  --region europe-west2 \
  --set-env-vars=OPENROUTER_API_KEY=YOUR_KEY,GCP_PROJECT=whetstone-500713,VERTEX_LOCATION=europe-west2

Note: Must be run from D:\Whetstone (not user home dir) to avoid WinError 1920 on pdf_env symlink.

[Copilot]

Pull request overview

Adds GCP-oriented deployment/documentation updates and a new frontend intro-video experience, while extending backend support for serving static assets and migrating existing SQLite session tables to include persona/difficulty.

Changes:

• Adds intro video overlay flow in the frontend, with Skip support and boot sequencing after video end/failure.
• Serves intro.mp4 and demo.png via new FastAPI routes.
• Updates SQLite initialization to include persona/difficulty columns and attempts to migrate older DBs; adds deployment/docs ignore rules and a new README.

Reviewed changes

Copilot reviewed 5 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
README.md	New project overview, features, local run + Cloud Run deployment instructions.
frontend/index.html	Adds fullscreen intro video overlay and defers app boot until skip/end/error.
backend/app/main.py	Adds /intro.mp4 and /demo.png routes to serve frontend assets.
backend/app/db.py	Adds schema migration for persona/difficulty columns on existing SQLite DBs.
.gitignore	Keeps *.md ignored while explicitly tracking README.md.
.gcloudignore	Excludes venvs, large data, and dev/team/docs files from Cloud Build source upload.

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[Vector897]

新增：五层防幻觉机制

新增文件 backend/app/engines/grounding.py

五层机制

1. Quote Verification（引用核实）
评分后逐条检查 evidence_quote 是否在实际对话记录中存在。SequenceMatcher 模糊匹配（阈值 0.65）。找不到 → verdict 降为 UNMET，注明 [GROUNDING: quote not found]。

2. Trigger Validation（触发条件验证）
对手声称触发让步前，先验证 trigger_claimed 是否与场景 JSON 中的 concession_triggers 语义相关（双重匹配：ratio ≥ 0.45 OR 关键词重叠 ≥ 40%）。不匹配 → 直接拒绝，不进入裁判流程。

3. Self-Consistency Referee（多数投票裁判）
Concession Gate 改为 3 次独立调用，多数票（2:1 以上）才允许让步。返回 _consistency_votes 字段可审计。

4. Score Sanity Check（分数钳位）
dimension_scores 每项钳位到 [0, max]；overall_score 钳位到 [0, 100]；类型强制转换。

5. Schema Guard（结构守卫）
三套 validator（对手/裁判/评分）。修正 conceded: true → True，填充缺失字段，reply 为空时替换占位符。