feat(ui): strengthen applicant Participate rail with Approve + Commit CTA

[MontrealAI]

Motivation

• Restore the flagship applicant flow so non-technical MetaMask users can approve stake and submit the real on-chain commitApplication(...) call directly from the main Participate surface.
• Remove the blocking UX gap where the primary commit path was only present in secondary helpers or local archives and not a visible, review-first on-chain action in the premium applicant panel.

Description

• Added an inline Approve stake + commit control (id="applicantApproveAndCommitButton") to the flagship applicant card (id="participateApplicantPanel") while keeping the dominant Commit application on-chain button visible and primary.
• Implemented submitApproveAndCommit() to perform stake approval to the Discovery spender, refresh on-chain readiness, then open the existing review-first commitApplication(...) write path that calls agiJobDiscovery.methods.commitApplication(...).
• Updated readiness/CTA logic so the new button is enabled only when the remaining blocker is an allowance shortfall, and blockers are always shown under the primary CTA (#applicantCommitBlockers) with explicit human-readable reasons.
• Preserved local packet utilities and demoted the archive copy by clarifying the advanced section (id="advancedLocalPacketArchive") text to: this is optional local packet storage and not the primary on-chain action surface.

Testing

• Verified presence of required IDs and labels via code search: participateApplicantPanel, applicantApproveStakeButton, applicantApproveAndCommitButton, applicantCommitApplicationButton, applicantRevealApplicationButton, and advancedLocalPacketArchive.
• Confirmed live write paths and hooks still exist by locating commitApplication( and revealApplication( in the main file and the wallet integration hooks eth_requestAccounts, wallet_switchEthereumChain, accountsChanged, and chainChanged.
• Ran smoke searches and static checks to ensure the new button is wired to submitApproveAndCommit() and that blocker/enabling logic is updated; these checks passed.
• Saved the single-file HTML with the changes and validated that the primary commit flow remains review-first and calls the real Discovery contract method for commit and reveal.

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Codex Task