[koculu]

Summary

Extract hardcoded functionality from ts-ssg into default plugins while preserving existing site output.

Changes

• Provide component, theme, and browser-script plugins through ts-components, ts-theme, and ts-page-scripts.
• Support customizing or disabling defaults without adding lifecycle hooks.
• Scope component registrations to each build and preserve complete head content for custom templates.
• Update plugin documentation and require future PR descriptions to follow this template.

Validation

• All 897 tests passed.
• Build, bundle, packaging, lint, formatting, and dependency checks passed.
• Compared isolated frontend publishes against 028e88f3: both produced 162 pages and 353 files, with no missing files or unexplained drift.
• HTML matches after cache-key normalization; CSS and search output are byte-identical. Seven JavaScript differences passed binding-aware syntax checks.