Improve Spanish dashboard translation

[Chytzo]

Summary

• Improve the Spanish dashboard translation for Spain Spanish across the web UI.
• Fix awkward or incorrect strings, punctuation, consistency, and untranslated/rough technical copy.
• Add missing Spanish Kanban translation keys for assignee-required states.

Validation

• npm run build from web/ passes.
• npx eslint src/i18n/es.ts from web/ passes.
• Translation key parity checked against en.ts: 606/606 keys, no missing or extra Spanish keys.

Note: full npm run lint still reports pre-existing unrelated React/compiler lint issues outside src/i18n/es.ts.

[teknium1]

Thanks for the translation pass. I verified the premise against current main: several rough/untranslated Spanish strings are still present, for example web/src/i18n/es.ts:33 has msjs, web/src/i18n/es.ts:181-182 has awkward analytics labels, and web/src/i18n/es.ts:639 still says Result.

Problems

• The PR is stale against current main. Commit 709e37e19e added Spanish scheduled Kanban strings, now visible at web/src/i18n/es.ts:712 and web/src/i18n/es.ts:722; the PR head's Kanban column block lacks those scheduled keys, so a direct salvage must not overwrite them.

Suggested changes

• Resolve the conflict by preserving current main's scheduled Kanban label/help while carrying over this PR's Spanish wording improvements and needsAssignee / needsAssigneeHint additions.
• Re-run the key-parity/typecheck validation after resolution, since web/src/i18n/en.ts:685-687 and web/src/i18n/types.ts:698-699 are the relevant assignee-required contract.

Automated hermes-sweeper review.