feat: add floating help chat widget, remove settings page

Add a documentation-grounded help chat assistant accessible from every
page via a floating button in the bottom-right corner.

Backend (compliance-agent):
- New POST /api/v1/help/chat endpoint
- Loads README.md + docs/**/*.md at first request (OnceLock cache)
- Excludes node_modules, uses walkdir for discovery
- Falls back to degraded prompt if docs not found
- Uses LiteLLM via existing chat_with_messages infrastructure

Dashboard (compliance-dashboard):
- New HelpChat component with toggle button, message area, input
- Styled to match Obsidian Control theme (dark, accent cyan)
- Renders in AppShell so it's available on every page
- Multi-turn conversation with history
- Server function proxies to agent API

Also:
- Remove Settings page (route, sidebar entry, page file)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

compliance-agent/src/api/handlers/help_chat.rs

@@ -0,0 +1,187 @@
+use std::path::{Path, PathBuf};
+use std::sync::OnceLock;
+
+use axum::extract::Extension;
+use axum::http::StatusCode;
+use axum::Json;
+use serde::{Deserialize, Serialize};
+use walkdir::WalkDir;
+
+use super::dto::{AgentExt, ApiResponse};
+
+// ── DTOs ─────────────────────────────────────────────────────────────────────
+
+#[derive(Debug, Deserialize)]
+pub struct HelpChatMessage {
+    pub role: String,
+    pub content: String,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct HelpChatRequest {
+    pub message: String,
+    #[serde(default)]
+    pub history: Vec<HelpChatMessage>,
+}
+
+#[derive(Debug, Serialize)]
+pub struct HelpChatResponse {
+    pub message: String,
+}
+
+// ── Doc cache ────────────────────────────────────────────────────────────────
+
+static DOC_CONTEXT: OnceLock<String> = OnceLock::new();
+
+/// Walk upward from `start` until we find a directory containing both
+/// `README.md` and a `docs/` subdirectory.
+fn find_project_root(start: &Path) -> Option<PathBuf> {
+    let mut current = start.to_path_buf();
+    loop {
+        if current.join("README.md").is_file() && current.join("docs").is_dir() {
+            return Some(current);
+        }
+        if !current.pop() {
+            return None;
+        }
+    }
+}
+
+/// Read README.md + all docs/**/*.md (excluding node_modules).
+fn load_docs(root: &Path) -> String {
+    let mut parts: Vec<String> = Vec::new();
+
+    // Root README first
+    if let Ok(content) = std::fs::read_to_string(root.join("README.md")) {
+        parts.push(format!("<!-- file: README.md -->\n{content}"));
+    }
+
+    // docs/**/*.md, skipping node_modules
+    for entry in WalkDir::new(root.join("docs"))
+        .follow_links(false)
+        .into_iter()
+        .filter_entry(|e| {
+            !e.path()
+                .components()
+                .any(|c| c.as_os_str() == "node_modules")
+        })
+        .filter_map(|e| e.ok())
+    {
+        let path = entry.path();
+        if !path.is_file() {
+            continue;
+        }
+        if path
+            .extension()
+            .and_then(|s| s.to_str())
+            .map(|s| !s.eq_ignore_ascii_case("md"))
+            .unwrap_or(true)
+        {
+            continue;
+        }
+
+        let rel = path.strip_prefix(root).unwrap_or(path);
+        if let Ok(content) = std::fs::read_to_string(path) {
+            parts.push(format!("<!-- file: {} -->\n{content}", rel.display()));
+        }
+    }
+
+    if parts.is_empty() {
+        tracing::warn!(
+            "help_chat: no documentation files found under {}",
+            root.display()
+        );
+    } else {
+        tracing::info!(
+            "help_chat: loaded {} documentation file(s) from {}",
+            parts.len(),
+            root.display()
+        );
+    }
+
+    parts.join("\n\n---\n\n")
+}
+
+/// Returns a reference to the cached doc context string, initialised on
+/// first call via `OnceLock`.
+fn doc_context() -> &'static str {
+    DOC_CONTEXT.get_or_init(|| {
+        let start = std::env::current_exe()
+            .ok()
+            .and_then(|p| p.parent().map(Path::to_path_buf))
+            .unwrap_or_else(|| PathBuf::from("."));
+
+        match find_project_root(&start) {
+            Some(root) => load_docs(&root),
+            None => {
+                // Fallback: try current working directory
+                let cwd = std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."));
+                if cwd.join("README.md").is_file() {
+                    return load_docs(&cwd);
+                }
+                tracing::error!(
+                    "help_chat: could not locate project root from {}; doc context will be empty",
+                    start.display()
+                );
+                String::new()
+            }
+        }
+    })
+}
+
+// ── Handler ──────────────────────────────────────────────────────────────────
+
+/// POST /api/v1/help/chat — Answer questions about the compliance-scanner
+/// using the project documentation as grounding context.
+#[tracing::instrument(skip_all)]
+pub async fn help_chat(
+    Extension(agent): AgentExt,
+    Json(req): Json<HelpChatRequest>,
+) -> Result<Json<ApiResponse<HelpChatResponse>>, StatusCode> {
+    let context = doc_context();
+
+    let system_prompt = if context.is_empty() {
+        "You are a helpful assistant for the Compliance Scanner project. \
+         Answer questions about how to use and configure it. \
+         No documentation was loaded at startup, so rely on your general knowledge."
+            .to_string()
+    } else {
+        format!(
+            "You are a helpful assistant for the Compliance Scanner project. \
+             Answer questions about how to use, configure, and understand it \
+             using the documentation below as your primary source of truth.\n\n\
+             Rules:\n\
+             - Prefer information from the provided docs over general knowledge\n\
+             - Quote or reference the relevant doc section when it helps\n\
+             - If the docs do not cover the topic, say so clearly\n\
+             - Be concise — lead with the answer, then explain if needed\n\
+             - Use markdown formatting for readability\n\n\
+             ## Project Documentation\n\n{context}"
+        )
+    };
+
+    let mut messages: Vec<(String, String)> = Vec::with_capacity(req.history.len() + 2);
+    messages.push(("system".to_string(), system_prompt));
+
+    for msg in &req.history {
+        messages.push((msg.role.clone(), msg.content.clone()));
+    }
+    messages.push(("user".to_string(), req.message));
+
+    let response_text = agent
+        .llm
+        .chat_with_messages(messages, Some(0.3))
+        .await
+        .map_err(|e| {
+            tracing::error!("LLM help chat failed: {e}");
+            StatusCode::INTERNAL_SERVER_ERROR
+        })?;
+
+    Ok(Json(ApiResponse {
+        data: HelpChatResponse {
+            message: response_text,
+        },
+        total: None,
+        page: None,
+    }))
+}

compliance-agent/src/api/handlers/mod.rs

@@ -4,6 +4,7 @@ pub mod dto;
 pub mod findings;
 pub mod graph;
 pub mod health;
+pub mod help_chat;
 pub mod issues;
 pub mod pentest_handlers;
 pub use pentest_handlers as pentest;

compliance-agent/src/api/routes.rs

@@ -99,6 +99,8 @@ pub fn build_router() -> Router {
             "/api/v1/chat/{repo_id}/status",
             get(handlers::chat::embedding_status),
         )
+        // Help chat (documentation-grounded Q&A)
+        .route("/api/v1/help/chat", post(handlers::help_chat::help_chat))
         // Pentest API endpoints
         .route(
             "/api/v1/pentest/lookup-repo",