Update project dependencies #432

Objective

Bring all project dependencies up to their latest stable versions, resolving breaking changes and verifying compatibility across the build, test, and runtime pipelines.

Rationale

Several core dependencies are multiple major versions behind (wagmi 2->3, vite 6->8, typescript 5->6, zod 3->4, biome 1->2). Deferring updates increases the cost of future upgrades and risks missing security patches and performance improvements.

Branching strategy

All work happens on a shared chore/update-deps branch created from develop. Child issues use incremental sub-branches that target the previous issue's branch via stacked PRs. When all child PRs are merged, a single PR from chore/update-deps into develop closes the epic.

PR chain:

1. Update safe dependencies (patches + minors) #434 -- chore/update-deps -> develop (chore: update safe dependencies #437)
2. Update medium-risk dependencies #435 -- chore/update-medium-risk-deps -> chore/update-deps (chore: update medium-risk dependencies #439)
3. Update high-risk dependencies #436 -- sub-branch -> chore/update-medium-risk-deps (or whichever branch is current after Update medium-risk dependencies #435 merges)

Each PR only contains the diff for its own issue. Merge order follows the numbering above.

Scope

In scope:

• All outdated packages identified by pnpm outdated as of 2026-04-01
• Config and code changes required by breaking upgrades
• Verification via lint, test, and build

Out of scope:

• Feature work or refactoring unrelated to the upgrades
• wagmi 2->3 implementation (tracked separately after the spike)

Acceptance criteria

• All child issues are resolved
• pnpm lint && pnpm test && pnpm build pass on main after all PRs merge
• Manual smoke test: dev server starts, app loads, wallet connects, network switching works, contract interactions succeed
• No regressions in wallet connection, chain switching, or contract interaction flows

Issue breakdown

• Research wagmi 2->3 migration path #433 -- Spike: Research wagmi 2->3 migration path
• Update safe dependencies (patches + minors) #434 -- Update safe dependencies (patches + minors)
• Update medium-risk dependencies #435 -- Update medium-risk dependencies
• Update high-risk dependencies #436 -- Update high-risk dependencies