Add Web Push, guided start screen, SVG icons, chunked uploads, rename

- Web Push (VAPID + RFC 8291, pure Rust): permission/question/finished
  notifications while no app window is visible; settings with test button
- Guided new-session flow: task, craft target (website/app/game/old
  software/fresh), clean room or deep, description, model, folder
  (new, existing or cloned git repository); originals upload to original/
- Craft phase bar (craft_phase tool) for study/specify/build/check/ready
- Chunked uploads (8 MB) up to server.max_upload_mb (default 500 MB)
- All UI glyphs and emojis replaced by themeable SVG icons
- Rename dialog with manual name or model-generated suggestion

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/src/prompts.rs

@@ -50,7 +50,7 @@ const BUILD_PROMPT: &str = "Mode: BUILD. You have full access to read, modify an
 const PLAN_PROMPT: &str = r#"Mode: PLAN. You are in read-only planning mode: you must not modify files, run state-changing commands or make commits.
 Investigate the codebase, ask clarifying questions with ask_user where requirements are ambiguous, and finish with a concrete, step-by-step implementation plan (files to change, approach, risks, verification). The user switches to build mode to execute it."#;
 
-const CRAFT_PROMPT: &str = r#"Mode: CRAFT. You recreate the look and behaviour of a target (website, app or game) as a NEW, original project the user owns, working in four phases. Keep the user informed of the current phase with todo_write (one item per phase).
+const CRAFT_PROMPT: &str = r#"Mode: CRAFT. You recreate the look and behaviour of a target (website, app or game) as a NEW, original project the user owns, working in phases. Report each phase with craft_phase when you enter it (study, specify in deep mode, build, check, ready) – the user sees it as a progress bar; use todo_write for the steps inside a phase.
 
 1. STUDY – Inspect the target. For websites use browser_snapshot on each relevant page (it captures every configured screen width plus visible text). Note layout, colours, typography, spacing, components, navigation and behaviour. For apps/games use screenshots the user provides and their description. Summarise your findings briefly.
 2. BUILD – Create the new project in the working directory, in the stack the user asked for (otherwise a sensible default: plain HTML/CSS/JS for sites). Write clean, original code and original placeholder content/assets; do not copy proprietary text, logos, images or code.