refactor: move session management & port allocation to backend

[qnixsynapse]

Describe Your Changes

• Remove the in‑process activeSessions map and its cleanup logic from the TypeScript side.
• Introduce new Tauri commands in Rust:
  • get_random_port – picks an unused port using a seeded RNG and checks availability.
  • find_session_by_model – returns the SessionInfo for a given model ID.
  • get_loaded_models – returns a list of currently loaded model IDs.
• Update the extension’s TypeScript code to use these commands via invoke:
  • findSessionByModel, load, unload, chat, getLoadedModels, and embed now operate asynchronously and query the backend.
  • Remove the old is_port_available command and the custom port‑checking loop.
  • Simplify onUnload – session termination is now handled by the backend.
• Drop unused helpers (sleep, waitForModelLoad) and related port‑availability code.
• Add missing Rust imports (rand::{StdRng,Rng,SeedableRng}, HashSet) and improve error handling.
• Register the new commands in src-tauri/src/lib.rs (replace is_port_available with the three new commands).

This refactor centralises session state and port allocation in the Rust backend, eliminates duplicated logic, and resolves race conditions around model loading and session cleanup.

Fixes Issues

• Closes bug: FE doesn't save states on hot reload #6082

Self Checklist

• Added relevant comments, esp in complex areas
• Updated docs (for bug fixes / features)
• Created issues for follow-up changes or refactoring needed

---

Important

Refactor session management and port allocation to Rust backend, removing TypeScript activeSessions map and adding new Tauri commands.

• Behavior:
  • Remove activeSessions map and cleanup logic from TypeScript in index.ts.
  • Add Tauri commands in Rust: get_random_port, find_session_by_model, get_loaded_models in server.rs.
  • Update TypeScript to use new commands via invoke: findSessionByModel, load, unload, chat, getLoadedModels, embed.
  • Remove is_port_available command and custom port-checking loop.
  • Simplify onUnload in index.ts to let backend handle session termination.
• Code Cleanup:
  • Drop unused helpers sleep, waitForModelLoad in index.ts.
  • Add missing Rust imports and improve error handling in server.rs.
• Command Registration:
  • Register new commands in lib.rs, replacing is_port_available with new commands.

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[ellipsis-dev]

Caution

Changes requested ❌

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1. extensions/llamacpp-extension/src/index.ts:1459

• Draft comment:
  The error message in the chat method says 'Model have crashed!'. Consider correcting the grammar to 'Model has crashed!' for clarity.
• Reason this comment was not posted:
  Confidence changes required: 33% <= threshold 50% None

2. src-tauri/src/core/utils/extensions/inference_llamacpp_extension/server.rs:202

• Draft comment:
  The raw string literal used for trimming the UNC prefix (i.e. r"\?") may not be correctly formed. Consider using an alternative raw string syntax (for example, r#"\?"#) to ensure it parses correctly.
• Reason this comment was not posted:
  Comment was not on a location in the diff, so it can't be submitted as a review comment.

3. src-tauri/src/lib.rs:95

• Draft comment:
  The registration of the new Tauri commands (get_random_port, find_session_by_model, get_loaded_models) for session management and port allocation is correctly integrated.
• Reason this comment was not posted:
  Confidence changes required: 0% <= threshold 50% None

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[github-actions]

Barecheck - Code coverage report

Total: 33.17%

Your code coverage diff: -0.01% ▾

✅ All code changes are covered

[louis-menlo]

Works great & LGTM.