fix: add length limits on prompt title and body

[rahulkr182]

Resolves #95. Adds length check constraints in the DB as abuse backstops and explicit validations in the UI for prompt upload.

[strix-security]

Strix Security Review

No security issues found.

_{Updated for 3a809b4.}

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Reviewed by Strix
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[github-actions]

Thanks for the pull request, @rahulkr182. A couple of things from CONTRIBUTING.md before this can be reviewed:

• You have 5 open pull requests (fix: add length limits on prompt title and body #133, fix: unify prompt card actions across screen widths and align breakpoints #116, fix: resolve five accessibility problems #115, perf: add search and tag indexes #112, chore: delete dead code (#104) #110). The limit is 2, so this one will wait until one of the others is merged or closed.
• bug: no length limit on prompt title or body #95 is not assigned to you. Please comment on the issue with your plan and wait to be assigned before starting.

Review is done by one person in their spare time, so these rules keep the queue moving for everyone.

[klprakhar]

@rahulkr182 Please follow the contribution guidelines before opening more PRs. The contributing guide clearly states: “Two open pull requests at most. Don't claim another issue until one of yours is merged or closed.”

You already have multiple open PRs, and two of them currently have changes requested. Please focus on addressing the requested changes in your existing PRs and get them merged/closed before opening or claiming another issue.

Please stick to the contribution rules going forward.