Finish bundled-template migration; simplify frontmatter; de-duplicate toolbar/menu

Completes the move off the external cookiecutter tool: drops
src/cookiecutter.rs and the cookiecutter_bin/Template-path setting now
that scaffolding always runs through the built-in MiniJinja engine,
and rewrites default_project_template() to walk up from the executable
without panicking when the bundled template can't be found. Rounds
out the snowflake template with the remaining 06-Revisions,
07-Final, 08-Covers and 09-Archive folders.

Simplifies the scene/chapter YAML frontmatter (drops type/word_count_min/
word_count_max in favor of status + a flat characters list) and updates
the new-file template, header parsing, outline, file list and Story
Bible editor to match.

Separately, de-duplicates the toolbar and menu bar: settings that only
existed as always-visible toolbar controls (draft marker, zero-pad,
spell-check toggle, dictionary picker) move into their Settings
windows, toolbar buttons that exactly duplicated a menu item are
dropped, and toolbar-only actions with no menu path (open project
folder, git sync/init) gain one under File. Also fixes two ambiguous
menu labels: the Story Bible editor now reads "Story Bible editor…"
next to "Story Bible…" in Tools instead of sharing a label with Edit,
and Settings' "New project…" is now "New-project settings…" so it
doesn't read like File's actual create action.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

templates/snowflake/{{ cookiecutter.project_name }}/05-First Draft/_template.md

@@ -1,21 +1,22 @@
 ---
-# Basic metadata for your scene/chapter
-# Everything after the closing --- is your draft content
-
-id: ""
+# Everything this scene knows about itself lives here.
+# Below the closing --- is the draft, and nothing else:
+# that is what the word count counts and what gets exported.
 title: "New Scene Title"
 slug: ""
 act: 1
 chapter: 1
 scene: 1
-type: scene
 status: draft
-word_count_target: 2000
 pov: ""
 characters: []
 setting: ""
 date: ""
 time: ""
+conflict: ""
+theme: ""
+tone: ""
+word_count_target: 1800-2200
 ---
 
 [Write your scene content here...]