feat: add Firefly III template

[BinkyTwin]

/claim #152

Summary

• add a Firefly III template for self-hosted personal finance management
• include MariaDB persistence, the Firefly III Data Importer, and the scheduled cron trigger used by the official Docker setup
• configure Dokploy domains for the main app and importer, generated app/cron secrets, database credentials, timezone, and language

Closes #873.
Refs #152 as a partial template-bounty contribution.

Verification

• node dedupe-and-sort-meta.js
• node --import ./build-scripts/node_modules/tsx/dist/loader.mjs build-scripts/validate-template.ts --dir blueprints/firefly-iii
• node --import ./build-scripts/node_modules/tsx/dist/loader.mjs build-scripts/validate-docker-compose.ts --file blueprints/firefly-iii/docker-compose.yml
• git diff --check
• docker compose -f blueprints/firefly-iii/docker-compose.yml config
• docker manifest inspect fireflyiii/core:version-6.6.2
• docker manifest inspect fireflyiii/data-importer:version-2.3.2
• docker manifest inspect mariadb:11.8
• docker manifest inspect alpine:3.22

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Name	Status	Preview	Last Commit
templates	✅ Ready (View Log)	Visit Preview	4860544

[Copilot]

Pull request overview

Adds a new Dokploy blueprint for deploying Firefly III (personal finance manager) with its MariaDB database, the official data importer, and a scheduled cron-trigger container, plus the corresponding metadata entry.

Changes:

• Added blueprints/firefly-iii/ including docker-compose.yml, template.toml, and a logo asset.
• Configured Dokploy domains and environment variables (app URL/keys, DB credentials, timezone, language, cron token).
• Registered the new template in meta.json with links, tags, and version.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 2 comments.

File	Description
meta.json	Adds the firefly-iii entry to the central templates index.
blueprints/firefly-iii/template.toml	Defines variables, Dokploy domain routing for app/importer, and environment wiring.
blueprints/firefly-iii/docker-compose.yml	Introduces the Firefly III + MariaDB + importer + cron service stack.
blueprints/firefly-iii/firefly-iii.svg	Adds the template logo referenced by meta.json.

[BinkyTwin]

Updated in 4860544: VANITY_URL now uses an explicit FIREFLY_III_VANITY_URL env var instead of reusing APP_URL directly.

I kept the default value pointed at the public Firefly III app URL (http://${main_domain}), because the Firefly III data-importer docs describe FIREFLY_III_URL as the internal Docker URL and VANITY_URL as the public URL the importer should use when linking back to Firefly III: https://docs.firefly-iii.org/how-to/data-importer/installation/docker/