Implements Notary Proofs

[Step7750]

Mega-PR that provides E2E functionality for computing tlsn proofs. There will be a few follow ups for submitting proofs and auto-computing them in certain circumstances.

Overview:

• New NOTARY_PROVE method for external communication
• New bridge layer for service worker <-> offscreen communication
• Decent chunk of auxiliary bootstrapping in order to load WASM (ie. mutated CSP, headers)
• Permits only one ongoing proof at a time -- likely a good idea regardless since CPU can briefly spike during proof gen

Firefox is not supported: It appears to not be possible to set Cross-Origin-Embedder-Policy and Cross-Origin-Opener-Policy headers on the FF background page itself (dynamic MV3 header rewrite rules were a no-go as well). Given the small % that FF makes up on the site, we can likely shift them to the app to complete associated tasks.

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Note

Introduce TLSNotary-based proof generation via a new NOTARY_PROVE API using an offscreen document with web worker threads, plus required CSP, build, and dependency updates.

• Notary/TLSN proofs:
  • Add NOTARY_PROVE request (src/lib/bridge/handlers/notary_prove.ts) with concurrency limiting (MaxConcurrency) and new RequestType.NOTARY_PROVE.
  • Define proof request types and Steam URL builder (src/lib/notary/types.ts, src/lib/notary/utils.ts).
  • Offscreen infrastructure:
    • Message client (src/offscreen/client.ts), handlers map and TLSN prove handler (src/offscreen/handlers/{handlers.ts,notary_prove.ts,types.ts}).
    • Offscreen bootstrap and lifecycle (src/offscreen/{offscreen.html,offscreen.ts,utils.ts}), worker exposing tlsn-js via comlink (src/offscreen/worker.ts).
    • Initialize threads and compute presentations; estimate HTTP sizes for TLSN.
  • Environment config adds notary endpoints and logging levels (src/environment*.ts).
• Build/config:
  • manifest.json: set minimum_chrome_version 109, add offscreen permission, and content_security_policy.extension_pages for WASM.
  • webpack.config.js: include offscreen entry, copy TLSN WASM/assets, Provide Buffer, add COEP/COOP dev headers, dev host permissions; filter offscreen permission for Firefox.
  • tsconfig.json: change module to es2022.
  • Dependencies: add tlsn-js, comlink, buffer.
• Misc:
  • Add wait(ms) utility (src/lib/utils/snips.ts).

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[GODrums]

A few optional minor improvements. Overall, super impressive technology though.