Backend should not depend on HOME or host filesystem mirroring

[changhoon-sung]

Problem

The current backend crosses the client/backend boundary.

Today the backend requires a bind mount of the client host filesystem, effectively /Users/<username>, so it can resolve absolute local paths persisted as provenance.source_uri.

That is the wrong abstraction.

A backend should not depend on:

• client HOME
• client absolute paths
• host filesystem visibility
• path mirroring inside the container

This is both:

• a privacy/security issue — mounting HOME is far too broad
• an architecture issue — the backend is not client-agnostic

Why this matters

The CLI is the client. The backend should only deal with:

• API payloads
• graph persistence
• query/analysis

It should not know where a repo lives on a user machine, how files are read, or what local path layout the client uses.

Right now we have path-coupled persistence and path-coupled backend behavior. That makes the system fragile, privacy-invasive, and harder to support across environments, runtimes, and future clients.

Proposed direction

Separate responsibilities cleanly.

Client responsibilities

• file discovery
• file reads
• hashing / caching
• parsing / patch generation
• absolute → workspace-relative path conversion

Backend responsibilities

• revisions
• persistence
• graph query
• conflict / map / analysis services

The backend should ingest structured facts, not read client files.

Required changes

1. Stop using host absolute paths as canonical source identity
2. Introduce workspace-scoped relative identity:
   • workspace_id
   • workspace_relative_path
3. Move ingestion/file access fully to the client side
4. Remove backend reliance on HOME bind mounts
5. Refactor backend joins and lookups away from absolute source_uri

Acceptance criteria

• backend runs without HOME or broad host bind mounts
• ingestion works from client-provided payloads only
• persisted source identity is workspace-scoped and relative
• backend query/analysis paths do not require filesystem access