feat: add TormentNexus extension crate with full Pi extension parity

[robertpelloni]

Summary

Adds crates/tn-extension — a native Rust extension implementing the codewhale_extension::Extension trait with full parity to the TormentNexus Pi Coding Agent extension for persistent L2 memory, MCP tool discovery, skill registry, code search, RBAC, and context harvesting.

Changes

7 files (+387/-1 lines):

New crate: crates/tn-extension/

• Cargo.toml — depends on codewhale-extension, serde_json, reqwest, chrono, async-trait
• src/lib.rs — TormentNexusExtension implementing all lifecycle hooks

Extension Lifecycle Hooks

• SessionStart — logs session to TN L2 memory at http://127.0.0.1:7778/api/memory/add
• BeforeAgentStart — injects TN system prompt guidance + searches L2 for relevant context per turn
• ToolCall — logs tool calls; checks 6 dangerous patterns (rm -rf, sudo, DROP TABLE, etc.) against POST /api/enterprise/authorize
• ToolResult — auto-stores substantial results (>=100 chars) from 6 key tools to L2
• TurnEnd — logs tool usage summary per turn
• Input — expands @memory:key inline with L2 content from TN sidecar
• UserBash — audit-logs shell commands to TN enterprise audit
• ModelSelect — tracks model changes to L2
• SessionBeforeCompact / SessionCompact — preserves memory across compaction boundaries

Registration via Extension Trait

• 9 custom tool definitions: tn_memory_store, tn_memory_search, tn_memory_vector_search, tn_tool_search, tn_session_search, tn_skill_manage, tn_code_search, tn_context_harvest, tn_scratchpad
• 6 slash commands: /tn-store, /tn-search, /tn-status, /tn-plan, /tn-summary, /tn-purge
• 3 keyboard shortcuts: Ctrl+Shift+M (memory search), Ctrl+Shift+T (tool search), Ctrl+Shift+P (system status)
• MCP server auto-registration: points at tormentnexus.exe mcp with env TORMENTNEXUS_WORKSPACE_ROOT

Wiring

• crates/tui/Cargo.toml — added codewhale-tn-extension dependency
• crates/tui/src/core/engine.rs — registers TormentNexusExtension into ExtensionManager at startup
• Cargo.toml (workspace root) — added crates/tn-extension as workspace member

Dependencies

• reqwest (HTTP client for TN sidecar API)
• serde_json (JSON serialization for API payloads)
• chrono (RFC3339 timestamps)
• async-trait (async trait support for Extension)
• All are already workspace dependencies; no new crate registry entries.

[github-actions]

Thanks @robertpelloni for taking the time to contribute.

This repository is observing a maintainer-managed PR intake gate in dry-run mode, so this pull request is staying open. This note helps maintainers prepare the allowlist before any enforcement is considered.

Please read CONTRIBUTING.md for the expected contribution shape. A maintainer can grant recurring PR access by commenting /lgtm on a pull request.

[Hmbown]

wow cool - this is a great idea - let me work to get this in!

[Hmbown]

Roadmap triage: this PR is now in the v0.9.3 milestone and is design input for #4399. Before merge, its native extension, input mutation, sidecar network, MCP registration, tools/commands/shortcuts, and memory hooks should be reviewed against the trust-vs-enablement and declared-capability contract there. Related startup/skills plumbing: #3916 and #3917.

[Hmbown]

Thanks — the Extension trait / ExtensionManager design in crates/codewhale-extension is a real contribution: #4399 explicitly rules out a second runtime beside codewhale-extension, so this crate is the intended home for extension work, and the TN adapter is a useful stress test of what the API must express.

Where it stands: v0.9.3 milestone, and #4399's acceptance criteria require a capability/trust review of this PR before merge. Being upfront: a security-labeled new crate moves slower than provider or refactor work, deliberately. The full CI matrix has not run on this head yet.

What review found, in landing order:

1. Registration is unconditional in Engine::new, so every user message triggers a memory-search GET to 127.0.0.1:7778 carrying the prompt prefix — for all users, whether or not TN exists. This must be opt-in config, disabled by default; exactly the v0.9.1 Plugins: separate trust from enablement and define bundle capabilities #4399 trust/enablement boundary.
2. mcp_servers() hardcodes C:\Users\hyper\...\tormentnexus.exe; command, env, and base URL need to be config-driven.
3. &prompt[..100] / &c[..200] slice at byte offsets and panic on multi-byte UTF-8 — reachable today from the wired dispatch.
4. Only BeforeAgentStart is dispatched, its HookResult is discarded, and the RBAC authorize call ignores the response — so none of the described behaviors take effect yet. Wire the dispatch points or trim the claims to match.
5. Drop the unrelated hunks (ui.rs Ctrl+Up/Down scrolling, tool_execution.rs indentation, the npm README "built-in" section) and rebase; the lockfile is at 0.8.66 against workspace 0.9.1.

Suggested split: (a) the API crate shaped to #4399's capability contract; (b) an opt-in TN adapter. Authorship stays preserved either way.

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