docs(dashboard): document project results sync workflow

[christso]

Bead: av-hbv.4

Summary:

• Document project-level results repo sync, local dirty metadata overlays, push behavior, and conflict handling.
• Distinguish source project sync from configured results repo sync.
• Add local-git Dashboard API coverage for pull, dirty metadata push, and blocked conflict state.

Verification from worker handoff:

• bun test apps/cli/test/commands/results/serve.test.ts
• bunx biome check apps/cli/test/commands/results/serve.test.ts apps/web/src/content/docs/docs/tools/dashboard.mdx
• bun --filter agentv typecheck
• bun --filter @agentv/web build
• bun --filter agentv test
• git diff --check

Integration note: branch was local-only during inventory and has now been pushed for review.