feat: clearer, disambiguated tool names across all surfaces (#520)

Renames 18 ambiguous or hard-to-search tool names so image tools self-qualify like the other modalities ("Compress" becomes "Compress Image"), and cleans up a few awkward names. Propagated across search (constants.ts), display (en.ts + 20 locales), the OpenAPI base spec + 20 locale specs, and the docs tool-page headings in 21 languages. Removes the duplicate "Normalize Audio" summary shared by the video and audio endpoints. Tool ids and routes are unchanged, so no API paths or bookmarks break.

apps/docs/tools/files/epub-convert.md

@@ -2,7 +2,7 @@
 description: Convert an EPUB to PDF, DOCX, HTML, or Markdown.
 ---
 
-# Convert EPUB {#convert-epub}
+# Convert from EPUB {#convert-epub}
 
 Convert an EPUB e-book to PDF, Word (DOCX), HTML, or Markdown. Remote resources inside the book are not fetched.
 

apps/docs/tools/files/yaml-json.md

@@ -2,7 +2,7 @@
 description: Convert between YAML and JSON, both directions.
 ---
 
-# YAML / JSON {#yaml-json}
+# Convert YAML / JSON {#yaml-json}
 
 Convert between YAML and JSON formats in both directions. Upload a YAML file to get JSON, or upload a JSON file to get YAML.