Fixes the wiki-layer collapse observed when batch-ingesting many sources on
overlapping themes: the cascade's LLM classifier kept routing new content
into the same existing pages under a generic 'Overview' section, leaving
merged pages with undifferentiated stacked prose.

* Route every merge into a dedicated 'From: <title>' section rather than
  the LLM-suggested topical one, so sequential merges stack as distinct,
  attributable blocks
* Add --no-merge flag to `alxia ingest` and the MCP ingest tool to force a
  brand-new wiki page per source and skip cascade planning entirely, for
  batch URL ingests where 1-source-per-page is the desired shape
* Thread no_merge through ingest_file, ingest_repo, and the CLI dispatchers
  (single file, url, directory, git repo)
* Tests for heading construction + end-to-end no_merge behavior
* Bump version to 0.34.0