Refactor project paths and handling, preserve query params, scope download/XML routes, and adapt template for canonical URLs

[cycomachead]

Refactor project routes to use canonical URL paths and scope API endpoints

This PR cleans up project URL handling by introducing a proper RESTful path for project pages, adding 301 redirects from legacy URLs, and emitting canonical link tags to ensure search engines always index the primary domain.

Changes

• New project route: /project?username=...&projectname=... → /users/:username/projects/:projectname as the canonical project show route
• Legacy redirect: GET /project with query params (including old user/project aliases) now issues a 301 redirect to the new path, preserving all parameters
• Canonical URL tag: The project page sets self.canonical_url using config.hostname (the primary domain), and views/layout/head.etlua emits a <link rel="canonical"> tag when present — ensuring secondary-domain requests still point canonically at the primary domain
• Model URLs updated: url_for('site') now returns the new /users/{username}/projects/{projectname} path; url_for('download') now returns /api/v1/project/{id}
• Client-side path generation: Cloud.prototype.showProjectPath updated to produce the new URL structure using encodeURIComponent
• api.lua unchanged: The project/:id route remains accessible via api_route (both /api/v1/project/:id and /project/:id) — no breaking change to the API

Reviewer Notes

• The api.lua route was intentionally not changed to hard-scope under /api/v1/ — that change was reverted per feedback. The model's download URL now emits the namespaced form, but the legacy short path remains supported server-side.
• The legacy /project GET handler normalizes the old user/project param aliases and lowercases usernames to match the global before_filter behavior.

---

Superconductor Ticket Implementation | App Preview | Guided Review