Reject ambiguous session navigation targets #897

Problem

hunk session navigate does not consistently enforce one complete navigation mode across the CLI and daemon API.

Two invalid or ambiguous requests currently pass validation:

1. Directional navigation can be combined with absolute targets, for example:

   hunk session navigate <session-id> --next-comment --file src/app.ts --hunk 2

   Directional navigation wins and the file/hunk arguments are silently ignored.

2. The daemon accepts absolute hunk or line navigation without filePath. It dispatches the command, but the live terminal cannot resolve an absolute target without a file.

These behaviors predate the comment-ID cleanup in #896, but that work makes the remaining validation gap explicit at the broker boundary.

Expected behavior

Navigation should select one complete mode:

• comment ID: commentId only;
• direction: commentDirection only;
• absolute location: filePath plus either a hunk number or complete side/line coordinates.

For compatibility, a raw API request containing complete line coordinates alongside a hunk number may continue to prefer the exact line, but this precedence should be explicit and tested.

Acceptance criteria

• Reject directional navigation combined with file, hunk, or line targets in both CLI and daemon validation.
• Require filePath for daemon hunk and line navigation.
• Preserve the documented exact-line precedence for compatible raw API requests.
• Add CLI and broker regression tests for accepted and rejected mode combinations.
• Keep the terminal bridge as a pass-through adapter.
• Add a patch Changeset for the validation fix.

Context

• Feature: feat(session): navigate to comments by id #845
• Broker canonicalization cleanup: refactor(session): canonicalize comment navigation #896

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