Fix license creation toast message

[C2015]

Description

Fixes #1417.

This updates the add-license modal so a successfully created license shows the license-specific success toast instead of reusing the project creation message.

The change also adds the new license_created i18n key across the existing locale files.

Testing

• npx eslint src/views/portfolio/licenses/LicenseAddLicenseModal.vue --report-unused-disable-directives
• node -e "const fs=require('fs'); for (const f of fs.readdirSync('src/i18n/locales')) { const p='src/i18n/locales/'+f; const data=JSON.parse(fs.readFileSync(p,'utf8')); if (!data.message?.license_created) throw new Error(f+' missing license_created'); } console.log('all locale files contain message.license_created');"
• npm run build

Note: npm run vue-i18n-extract currently fails before reporting missing/unused keys with EISDIR: illegal operation on a directory, read in vue-i18n-extract. Full-repo npm run eslint also fails on pre-existing repository-wide lint issues unrelated to this change.