Kill reqwest — minimal HTTP client on raw hyper + tokio-rustls

New src/agent/api/http.rs: ~240 lines, supports GET/POST, JSON/form
bodies, SSE streaming via chunk(), TLS via rustls. No tracing dep.

Removes reqwest from the main crate and telegram channel crate.
Cargo.lock drops ~900 lines of transitive dependencies.

tracing now only pulled in by tui-markdown.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/agent/tools/web.rs

@@ -27,11 +27,10 @@ async fn web_fetch(args: &serde_json::Value) -> Result<String> {
     let a: FetchArgs = serde_json::from_value(args.clone())
         .context("invalid web_fetch arguments")?;
 
-    let client = http_client()?;
-    let response = client.get(&a.url)
-        .header("User-Agent", "consciousness/0.3")
-        .send()
-        .await
+    let client = http_client();
+    let response = client.get_with_headers(&a.url, &[
+        ("user-agent", "consciousness/0.3"),
+    ]).await
         .with_context(|| format!("failed to fetch {}", a.url))?;
 
     let status = response.status();
@@ -61,7 +60,7 @@ async fn web_search(args: &serde_json::Value) -> Result<String> {
         .context("invalid web_search arguments")?;
 
     // Use DuckDuckGo HTML search — no API key needed
-    let client = http_client()?;
+    let client = http_client();
     let encoded: String = a.query.chars().map(|c| {
         if c.is_ascii_alphanumeric() || c == '-' || c == '_' || c == '.' {
             c.to_string()
@@ -72,10 +71,9 @@ async fn web_search(args: &serde_json::Value) -> Result<String> {
         }
     }).collect();
     let url = format!("https://html.duckduckgo.com/html/?q={}", encoded);
-    let response = client.get(&url)
-        .header("User-Agent", "consciousness/0.3")
-        .send()
-        .await
+    let response = client.get_with_headers(&url, &[
+        ("user-agent", "consciousness/0.3"),
+    ]).await
         .context("search request failed")?;
 
     let body = response.text().await
@@ -86,20 +84,16 @@ async fn web_search(args: &serde_json::Value) -> Result<String> {
     for chunk in body.split("class=\"result__body\"") {
         if results.len() >= a.num_results { break; }
         if results.is_empty() && !chunk.contains("result__title") {
-            // Skip the first split (before any results)
             continue;
         }
 
-        // Extract title
         let title = extract_between(chunk, "class=\"result__a\"", "</a>")
             .map(strip_tags)
             .unwrap_or_default();
 
-        // Extract URL
         let href = extract_between(chunk, "href=\"", "\"")
             .unwrap_or_default();
 
-        // Extract snippet
         let snippet = extract_between(chunk, "class=\"result__snippet\"", "</a>")
             .map(strip_tags)
             .unwrap_or_default();
@@ -118,30 +112,37 @@ async fn web_search(args: &serde_json::Value) -> Result<String> {
 
 // ── Helpers ─────────────────────────────────────────────────────
 
-fn http_client() -> Result<reqwest::Client> {
-    reqwest::Client::builder()
+fn http_client() -> crate::agent::api::http::HttpClient {
+    crate::agent::api::http::HttpClient::builder()
         .timeout(std::time::Duration::from_secs(30))
         .build()
-        .context("failed to build HTTP client")
 }
 
 fn extract_between<'a>(text: &'a str, start: &str, end: &str) -> Option<&'a str> {
     let start_idx = text.find(start)? + start.len();
     // Skip past the closing > of the start tag
     let rest = &text[start_idx..];
-    let tag_end = rest.find('>')?;
-    let rest = &rest[tag_end + 1..];
-    let end_idx = rest.find(end)?;
-    Some(&rest[..end_idx])
+    let gt = rest.find('>')?;
+    let content_start = start_idx + gt + 1;
+    let content = &text[content_start..];
+    let end_idx = content.find(end)?;
+    Some(&content[..end_idx])
 }
 
-fn strip_tags(s: &str) -> String {
+fn strip_tags(html: &str) -> String {
     let mut out = String::new();
     let mut in_tag = false;
-    for ch in s.chars() {
-        if ch == '<' { in_tag = true; }
-        else if ch == '>' { in_tag = false; }
-        else if !in_tag { out.push(ch); }
+    for ch in html.chars() {
+        match ch {
+            '<' => in_tag = true,
+            '>' => in_tag = false,
+            _ if !in_tag => out.push(ch),
+            _ => {}
+        }
     }
-    out
+    out.replace("&amp;", "&")
+        .replace("&lt;", "<")
+        .replace("&gt;", ">")
+        .replace("&quot;", "\"")
+        .replace("&#x27;", "'")
 }