Feature: terraphim-agent search should output file paths + matching snippets/line numbers

[AlexMikhalev]

Problem

The terraphim-agent search command currently prints only rank + title, which makes it hard to use as a CLI for searching local notes/memory. For practical workflows (e.g. searching Clawdbot memory), we need file paths and a small snippet (or matching line numbers) to quickly locate the relevant source text.

Desired behavior

Add an option to terraphim-agent search to include source location and excerpt:

• Print rel_path (or uri) for each result
• Print matching line numbers (or a short snippet)
• Ideally also show the matched query terms

Example output (human):

• 1 MEMORY docs/src/clawdbot-memory/MEMORY.md:4
  WhatsApp gateway “flapping” mostly traced to an idle watchdog reconnect...

Notes

• Today the workaround is running rg -n "<query>" <haystack> manually; this feature would make terraphim-agent usable as a self-contained search CLI.
• Should work at least for the Ripgrep haystack backend.

Acceptance criteria

• terraphim-agent search --snippets "<query>" outputs path + line number(s) and a snippet per hit.
• Works in offline mode and server mode.