[codex] Harden verification, inputs, and frontend readiness

[ryan-wong-coder]

Summary

• Harden proof-bundle verification by binding receipts, global-log proofs, STH signatures, and anchor proofs to the signed claim and committed records.
• Tighten untrusted input handling across CBOR/JSON/admin/gRPC/SDK paths with strict trailing-data checks and response/body size limits.
• Fix admin static file path boundary handling and add regression coverage for traversal-style requests.
• Restore TrustDB favicon/app icon assets for Web Admin, Desktop frontend, and Wails packaging.
• Resolve frontend dependency audits by upgrading Vite/Vitest/tooling and pinning vulnerable transitive dev dependencies to fixed patch versions.

Linked Issue

None.

Scope Control

• This PR only changes files needed for the production-hardening work above.
• README / user-facing docs only describe behavior that is already implemented.
• No local data, keys, logs, backups, or unrelated draft files are included.

Proof Semantics

• No L1/L2/L3/L4/L5 semantic change.
• L4/L5 behavior is intentionally stricter: proofs now verify the STH signature and reject mismatched bundle/global-log/anchor bindings.
• .tdproof, .tdgproof, .tdanchor-result, .sproof, and .tdbackup formats remain unchanged.
• Compatibility impact is limited to rejecting malformed, unsigned, or inconsistently-bound proof material that previously could pass partial checks.

Storage, Recovery, and Scale

• No production path introduces full-scan, full-load, or full-recompute behavior.
• WAL, proofstore, global log, anchor outbox, backup, and desktop local storage boundaries are unchanged.
• Added/updated regression tests cover the changed validation and input-boundary behavior.

Validation

Local checks run:

• go test ./...
• go vet ./...
• cd clients/desktop && go test ./...
• cd clients/web && npm audit --json
• cd clients/web && npm run build
• cd clients/web && npm run test:unit
• cd clients/web && npm run test:e2e
• cd clients/desktop/frontend && npm audit --json
• cd clients/desktop/frontend && npm run build

GitHub Actions:

• CI is running on this PR; remaining checks will be monitored before merge.

Checks not run locally:

• go test -race ./...
• go test -tags=integration ./...
• go test -tags=e2e ./...
• cd clients/desktop && go test -race ./...
• cd clients/desktop && wails build

Risk / Rollback

• Risk is mainly stricter verification rejecting proof bundles that were malformed or only partially bound before.
• Rollback is reverting this PR; no data migration or storage format change is required.